tag:blogger.com,1999:blog-10503265645325449802024-03-18T22:43:06.128-04:00NumberADayWelcome to the Mathematical Association of America’s NumberADay blog! Every working day, we post a number and offer a selection of that number’s properties. Have a favorite number that you want to see profiled here? Shoot us an email at editor@maa.orgMathematical Association of Americahttp://www.blogger.com/profile/10559021045290192742noreply@blogger.comBlogger1551125tag:blogger.com,1999:blog-1050326564532544980.post-42913272366365897982015-03-10T16:15:00.001-04:002015-03-10T16:15:54.925-04:00<span style="text-align: center;">Thank you for following MAA NumberADay. We will no longer be updating this blog.</span>Mathematical Association of Americahttp://www.blogger.com/profile/10559021045290192742noreply@blogger.com0tag:blogger.com,1999:blog-1050326564532544980.post-53106972869813323482014-12-24T02:00:00.000-05:002014-12-24T02:00:01.507-05:002015<b>2015 </b>= 5 x 13 x 31.<br />
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<b>2015 </b>is palindromic in base 2 (binary): 11111011111 (<a href="http://oeis.org/A030130">A030130</a> and <a href="http://oeis.org/A168355">A168355</a>). <b>2015 </b>repeats the string <a href="http://maanumberaday.blogspot.com/2009/10/133.html">133</a> in base 4: 133133 (<a href="http://oeis.org/A020332">A020332</a>). It repeats the string <a href="http://maanumberaday.blogspot.com/2009/06/37.html">37</a> in base 8: 3737 (<a href="http://oeis.org/A020336">A020336</a>).<br />
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<b>2015 </b>is a <a href="http://en.wikipedia.org/wiki/Lucas%E2%80%93Carmichael_number">Lucas-Carmichael number</a> (<a href="http://oeis.org/A006972">A006972</a> and <a href="http://oeis.org/A129868">A129868</a>).<br />
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<a href="http://maanumberaday.blogspot.com/2013/12/2014.html">2014</a>, <b>2015</b>, and 2016 each have three distinct prime factors (sphenic numbers) (<a href="http://oeis.org/A168626">A168626</a>).<br />
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<b>2015 </b>is the sum of 10 distinct powers of 2 (<a href="http://oeis.org/A038461">A038461</a>).<br />
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<b>2015</b> is a number that cannot be written as a sum of three squares.<br />
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<b>2015 </b>divides 92<sup>4</sup> - 1.<br />
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgNEiwcU8Wy-GFUTJqOczf7q0dnrbeoPEU31DU0ElXpGsgqc6RYCJTPAxW3vO0prb3bzimhndXNm_kHDMzfFC-mY3DHsK6PTLZRgBPA9zbZ_xZ0OTCO4MWosieyAGLtmp-m8SeHbw2b3t8/s1600/n2015.jpg" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgNEiwcU8Wy-GFUTJqOczf7q0dnrbeoPEU31DU0ElXpGsgqc6RYCJTPAxW3vO0prb3bzimhndXNm_kHDMzfFC-mY3DHsK6PTLZRgBPA9zbZ_xZ0OTCO4MWosieyAGLtmp-m8SeHbw2b3t8/s1600/n2015.jpg" height="64" width="200" /></a></div>
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<b>2015 </b>is a year with exactly three "Friday the 13ths" (<a href="http://oeis.org/A190653">A190653</a>).<br />
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<b>2015 </b>is a year in which a blue moon occurs (a second full month to occur in a single calendar month) (<a href="http://oeis.org/A125680">A125680</a>).<br />
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The year <b>2015 </b>is the 100th anniversary of the founding of the Mathematical Association of America.<br />
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiWLKIrd8nxUNU5ty_IxxBzi4HA6Aq1_q6m_lAHqjaFqudHviwMk4sR7g6LiC7-k-vvxZ25Pv7mC58KOMP3NWkHFRDAa3QWsnhkEbsGiJZmLeLdWmO4w2cHApE3T5gN2QC_e-YuTK9YMjo/s1600/logo.png" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiWLKIrd8nxUNU5ty_IxxBzi4HA6Aq1_q6m_lAHqjaFqudHviwMk4sR7g6LiC7-k-vvxZ25Pv7mC58KOMP3NWkHFRDAa3QWsnhkEbsGiJZmLeLdWmO4w2cHApE3T5gN2QC_e-YuTK9YMjo/s1600/logo.png" height="62" width="320" /></a></div>
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Source: <a href="http://oeis.org/">OEIS</a>Mathematical Association of Americahttp://www.blogger.com/profile/10559021045290192742noreply@blogger.com0tag:blogger.com,1999:blog-1050326564532544980.post-76144264745781109982014-12-23T02:00:00.000-05:002014-12-23T02:00:03.517-05:006884<b>6884 </b>= 2 x 2 x 1721.<br />
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<b>6884</b> is the number of lines through at least two points of a 7 x 25 grid of points (<a href="http://oeis.org/A160847">A160847</a>).<br />
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<b>6884</b> has a representation as a sum of two squares: <b>6884 </b>= 22<sup>2</sup> + 80<sup>2</sup>.<br />
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhRSzbtK85_6qKl14UmeotHgydTEHP-Z-Qf1DxknsjiH-VjHXHoH_C8-6F4u_opcD6s7UZRdz4cOPK1Qr2JQcH6f9mnM8aEgaaf1JKZ0YdRBpIZjZwblcYkcUfQenROF1uj98xMOizwvgg/s1600/n6884.jpg" imageanchor="1" style="margin-left: 1em; margin-right: 1em; text-align: center;"><img border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhRSzbtK85_6qKl14UmeotHgydTEHP-Z-Qf1DxknsjiH-VjHXHoH_C8-6F4u_opcD6s7UZRdz4cOPK1Qr2JQcH6f9mnM8aEgaaf1JKZ0YdRBpIZjZwblcYkcUfQenROF1uj98xMOizwvgg/s1600/n6884.jpg" height="63" width="200" /></a><br />
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Source: <a href="http://oeis.org/">OEIS</a>Mathematical Association of Americahttp://www.blogger.com/profile/10559021045290192742noreply@blogger.com0tag:blogger.com,1999:blog-1050326564532544980.post-78156451098946121242014-12-22T03:00:00.000-05:002014-12-22T03:00:10.834-05:001853<b>1853</b>= 17 x 109.<br />
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<b>1853 </b>is a semiprime divisible by the sum of its digits (<a href="http://oeis.org/A118693">A118693</a>).<br />
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<b>1853 </b>is the sum of two positive cubes and divisible by 17 (<a href="http://oeis.org/A099178">A099178</a>).<br />
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<b> 1853</b> is a number <i>n</i> such that the strings <i>n</i>9<i>n</i> and 9<i>n</i>9 are both primes (<a href="http://oeis.org/A090265">A090265</a>).<br />
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<b>1853 </b>has two representations as a sum of two squares: <b>1853 </b>= 2<sup>2</sup> + 43<sup>2</sup> = 22<sup>2</sup> + 37<sup>2</sup>.<br />
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<b>1853 </b>is the hypotenuse of two primitive Pythagorean triples: <b>1853</b><sup>2</sup> = 172<sup>2</sup> + 1845<sup>2</sup> = 885<sup>2</sup> + 1628<sup>2</sup>.<br />
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<b>1853 </b>divides 33<sup>4</sup> - 1.<br />
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgI8lJQ6Z1s85fUw9Nb5T3PS-UN0-tn5Umyn3nkHvXrR4lEr-wgi6ysa5S5zjMbNGjwhN-OqChMw1rSmxMCKueJxCMjNKXk_lFklXu_KwUmfuKrJPEgFMyEWtIm7X0N8CkJIqD6tn-hjTI/s1600/n1853.jpg" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgI8lJQ6Z1s85fUw9Nb5T3PS-UN0-tn5Umyn3nkHvXrR4lEr-wgi6ysa5S5zjMbNGjwhN-OqChMw1rSmxMCKueJxCMjNKXk_lFklXu_KwUmfuKrJPEgFMyEWtIm7X0N8CkJIqD6tn-hjTI/s1600/n1853.jpg" /></a></div>
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Source: <a href="http://oeis.org/">OEIS</a><br />
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<br />Mathematical Association of Americahttp://www.blogger.com/profile/10559021045290192742noreply@blogger.com0tag:blogger.com,1999:blog-1050326564532544980.post-29058508263763681092014-12-19T03:00:00.000-05:002014-12-19T03:00:01.420-05:006881<b>6881 </b>= 7 x 983. It is the product of two distinct primes (<a href="http://oeis.org/A006881">A006881</a>).<br />
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<b>6881 </b>is a composite number not ending in 0 that yields a prime when turned upside down (<a href="http://oeis.org/A048889">A048889</a>).<br />
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The absolute difference between two consecutive digits of <b>6881 </b>in base 6 (51505) is greater than or equal to 4 (<a href="http://oeis.org/A032988">A032988</a>).<br />
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjhyphenhyphenxibbMc5qIiYSICdcrxJSIYhUXsungFzKzEr2fzsERV-_jy7QUhRFGw3-FzZGlpU0XvCgE0rH9JWSxEJYLIKxZBQUjWouW3Uplzgh1k55QJW_2QvUuhWIrbFjFVL7dWlVlx41AaDBGI/s1600/n6881.jpg" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjhyphenhyphenxibbMc5qIiYSICdcrxJSIYhUXsungFzKzEr2fzsERV-_jy7QUhRFGw3-FzZGlpU0XvCgE0rH9JWSxEJYLIKxZBQUjWouW3Uplzgh1k55QJW_2QvUuhWIrbFjFVL7dWlVlx41AaDBGI/s1600/n6881.jpg" height="106" width="200" /></a></div>
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Source: <a href="http://oeis.org/">OEIS</a>Mathematical Association of Americahttp://www.blogger.com/profile/10559021045290192742noreply@blogger.com0tag:blogger.com,1999:blog-1050326564532544980.post-38902663754860479882014-12-18T03:00:00.000-05:002014-12-18T03:00:18.814-05:007894<b>7894 </b>= 2 x 3947.<br />
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<b>7894 </b>is a number <i>n</i> for which <i>n</i> and 8<i>n</i> together use each digit from 1 to 9 exactly once (<a href="http://oeis.org/A115932">A115932</a>).<br />
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<b>7894 </b>is the number of isocent sequences of length 15 with exactly nine ascents (<a href="http://oeis.org/A243235">A243235</a>).<br />
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEj3cObcZXI4-Hei0B7TahV33zXf8p_odnB0AF2joUH1iyIguXjnywbFCfqtsELfjVHbjknPVXSoS7pXjhXZLyFVctbLczGFPGSUnMomHVOaWCWkK3QaZNMyzxqzFQaqIv-b2rDO0BLZaek/s1600/n7894.jpg" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEj3cObcZXI4-Hei0B7TahV33zXf8p_odnB0AF2joUH1iyIguXjnywbFCfqtsELfjVHbjknPVXSoS7pXjhXZLyFVctbLczGFPGSUnMomHVOaWCWkK3QaZNMyzxqzFQaqIv-b2rDO0BLZaek/s1600/n7894.jpg" height="91" width="200" /></a></div>
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Source: <a href="http://www2.stetson.edu/~efriedma/numbers.html">What's Special About This Number?</a>Mathematical Association of Americahttp://www.blogger.com/profile/10559021045290192742noreply@blogger.com0tag:blogger.com,1999:blog-1050326564532544980.post-91635852122948863682014-12-17T03:00:00.000-05:002014-12-17T03:00:16.679-05:003740<b>3740</b> = 2 x 2 x 5 x 11 x 17.<br />
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<b>3740 </b>is the sum of consecutive squares in two ways (<a href="http://oeis.org/A062681">A062681</a>).<br />
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<b>3740 </b>is 25152 in base 6 and 5115 in base 9.<br />
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<b>3740 </b>is the number of tatami tilings of a 3 x 10 grid (with monomers allowed) (<a href="http://oeis.org/A180970">A180970</a>).<br />
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<b>3740 </b>divides 21<sup>4</sup> - 1.<br />
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjeODhMMNv2R4jEAHbRFlGrampBQlFziyKAdQHBdpMespUNoBYdqzXb-gbPIDqWQNrd_bvXfpszHc5LE9US14PoHLZhh8GYhbJU25i9cqaDSEC03jlfCOup27NAhV08uAu9F9J9MQSJICI/s1600/n3740.jpg" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjeODhMMNv2R4jEAHbRFlGrampBQlFziyKAdQHBdpMespUNoBYdqzXb-gbPIDqWQNrd_bvXfpszHc5LE9US14PoHLZhh8GYhbJU25i9cqaDSEC03jlfCOup27NAhV08uAu9F9J9MQSJICI/s1600/n3740.jpg" height="65" width="200" /></a></div>
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Source: <a href="http://www2.stetson.edu/~efriedma/numbers.html">What's Special About This Number?</a>Mathematical Association of Americahttp://www.blogger.com/profile/10559021045290192742noreply@blogger.com0tag:blogger.com,1999:blog-1050326564532544980.post-18115377621430276852014-12-16T03:00:00.000-05:002014-12-16T03:00:05.286-05:001834<b>1834 </b>= 2 x 7 x 131.<br />
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<b>1834 </b>is an <a href="http://mathworld.wolfram.com/OctahedralNumber.html">octahedral number</a> (<a href="http://oeis.org/A005900">A005900</a>).<br />
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<b>1834</b> is the sum of the cubes of the first five primes (<a href="http://oeis.org/A098999">A098999</a>).<br />
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<b>1834 </b>is a number that has more different digits than its square (<a href="http://oeis.org/A061277">A061277</a>).<br />
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<b>1834 </b>is 3452 in base 8.<br />
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<b>1834 </b>divides 99<sup>13</sup> - 1.<br />
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjQ4guhVYAKxZQvBBYORY9ioKb_HIXVj_EcYnYpob8PLscGDOOAf4NuJSr34pqSMIs23MIqMA9TMPV_m4yaVb8OjYCASexg4902ZGsQA4pC6_fi55SpBQimnUtxrzy23OPAU078ZJtA2oQ/s1600/n1834.jpg" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjQ4guhVYAKxZQvBBYORY9ioKb_HIXVj_EcYnYpob8PLscGDOOAf4NuJSr34pqSMIs23MIqMA9TMPV_m4yaVb8OjYCASexg4902ZGsQA4pC6_fi55SpBQimnUtxrzy23OPAU078ZJtA2oQ/s1600/n1834.jpg" /></a></div>
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Source: <a href="http://www2.stetson.edu/~efriedma/numbers.html">What's Special About This Number?</a>Mathematical Association of Americahttp://www.blogger.com/profile/10559021045290192742noreply@blogger.com0tag:blogger.com,1999:blog-1050326564532544980.post-83909891956029555672014-12-15T03:00:00.000-05:002014-12-15T03:00:10.594-05:007799<b>7799</b> = 11 x 709.<br />
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<b>7799 </b>is a semiprime made up of two rums of identical digits (<a href="http://oeis.org/A116063">A116063</a>).<br />
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<b>7799 </b>is the least semiprime whose sum of prime factors equals 6! (<a href="http://oeis.org/A193216">A193216</a>).<br />
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The sum of the digits of <b>7799 </b>is 8 times the number of digits (<a href="http://oeis.org/A061425">A061425</a>).<br />
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<b>7799 </b>divides 96<sup>20</sup> - 1.<br />
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjq8SXMilVQAFL-FKDsO4XG1OCNXx-so-qnBUVnKIo2Ck14uclaR7SByL28109zoV1YFr_LzcaQkSUupmvLk9xDvghy4OzPFaFQj3nZC_oCDcBX1MmQrxntKk7ZV8u2SSIAvM83tqgXbRc/s1600/n7799.jpg" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjq8SXMilVQAFL-FKDsO4XG1OCNXx-so-qnBUVnKIo2Ck14uclaR7SByL28109zoV1YFr_LzcaQkSUupmvLk9xDvghy4OzPFaFQj3nZC_oCDcBX1MmQrxntKk7ZV8u2SSIAvM83tqgXbRc/s1600/n7799.jpg" height="71" width="200" /></a></div>
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Source: <a href="http://oeis.org/">OEIS</a>Mathematical Association of Americahttp://www.blogger.com/profile/10559021045290192742noreply@blogger.com0tag:blogger.com,1999:blog-1050326564532544980.post-24887379602065505732014-12-12T03:00:00.000-05:002014-12-12T03:00:10.394-05:006723<b>6723 </b>= 3 x 3 x 3 x 3 x 83.<br />
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<b>6723 </b>is a value of <i>n </i>for which 3<i>n</i> and 8<i>n</i> together use each digit from 0 to 9 exactly once.<br />
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<b>6723 </b>is 25413 in base 7.<br />
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<b>6723 </b>is the solution to the postage stamp problem with 3 denominations and 47 stamps (<a href="http://oeis.org/A001208">A001208</a>).<br />
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<b>6723 </b>is the maximum number of points visible from some point in a cubic 20 x 20 x 20 lattice (<a href="http://oeis.org/A141227">A141227</a>).<br />
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjY3p7rn9P9TxiKCNOQowNgfSnkpzW2YnNvJOSNIc2PsYnvidq2oQ8tkxEvOboxXTENJ1l86MXZ5Jzhuxw_eAAjrVDvB04MI29mEB3byOg6QukEsFsbvhFTcYzygnqgFyTrx3NtOd7hEcc/s1600/n6723.jpg" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjY3p7rn9P9TxiKCNOQowNgfSnkpzW2YnNvJOSNIc2PsYnvidq2oQ8tkxEvOboxXTENJ1l86MXZ5Jzhuxw_eAAjrVDvB04MI29mEB3byOg6QukEsFsbvhFTcYzygnqgFyTrx3NtOd7hEcc/s1600/n6723.jpg" height="84" width="200" /></a></div>
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Source: <a href="http://www2.stetson.edu/~efriedma/numbers.html">What's Special About This Number?</a>Mathematical Association of Americahttp://www.blogger.com/profile/10559021045290192742noreply@blogger.com0tag:blogger.com,1999:blog-1050326564532544980.post-61662461214247546892014-12-11T03:00:00.000-05:002014-12-11T03:00:08.238-05:006675<b>6675 </b>= 3 x 5 x 5 x 89.<br />
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<b>6675 </b>is a composite number that is the sum of two, three, four, and five consecutive composite numbers (<a href="http://oeis.org/A151745">A151745</a>).<br />
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<b>6675 </b>is a number <i>n</i> such that <i>n </i>and the square of <i>n</i> use only the digits 2, 4, 5, 6, and 7 (<a href="http://oeis.org/A137094">A137094</a>).<br />
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<b>6675</b> is 25314 in base 7.<br />
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<b>6675 </b>divides 34<sup>20</sup> - 1.<br />
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEi2kPYEKgm4DqbJ-eJOFi0fBucLLHhU2f9bjOWIkw8vODHZdC1Rcqceq_msDUEGfMRnqzBw9GD-5B4hgvhsV5TVhxbGjE4_mS5BMxcfaYj5-F9w4NWebFCYracj7nXiR_htHTrOoxH_61I/s1600/n6675.jpg" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEi2kPYEKgm4DqbJ-eJOFi0fBucLLHhU2f9bjOWIkw8vODHZdC1Rcqceq_msDUEGfMRnqzBw9GD-5B4hgvhsV5TVhxbGjE4_mS5BMxcfaYj5-F9w4NWebFCYracj7nXiR_htHTrOoxH_61I/s1600/n6675.jpg" /></a></div>
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Source: <a href="http://oeis.org/">OEIS</a>Mathematical Association of Americahttp://www.blogger.com/profile/10559021045290192742noreply@blogger.com0tag:blogger.com,1999:blog-1050326564532544980.post-38908707285147672812014-12-10T03:00:00.000-05:002014-12-10T03:00:10.641-05:004351<b>4351 </b>= 19 x 229.<br />
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The sum of the digits of <b>4351</b> is equal to the sum of the digits of its largest prime factor (<a href="http://oeis.org/A219340">A219340</a>).<br />
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<b>4351 </b>is a centered decagonal number (<a href="http://oeis.org/A062786">A062786</a>).<br />
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<b>4351 </b>is the concatenation of the 14th prime number and the 14th lucky number (<a href="http://oeis.org/A032603">A032603</a>).<br />
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<b>4351 </b>divides 94<sup>6</sup> - 1.<br />
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<b>4351 </b>is a number that cannot be written as a sum of three squares.<br />
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgPTcq751jd4c2H3TvSvviH0-bTjFLvImhig2rADngjw22sqZJs6JK6HoaY4tn3oNr8PbSaxV7GqO-Loydbr1j8G1kfjlrPNKtNJZZ7py76CFVOsU4Lsa2Q3O7K1_ZIw318P_9weN7tqzI/s1600/n4351.jpg" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgPTcq751jd4c2H3TvSvviH0-bTjFLvImhig2rADngjw22sqZJs6JK6HoaY4tn3oNr8PbSaxV7GqO-Loydbr1j8G1kfjlrPNKtNJZZ7py76CFVOsU4Lsa2Q3O7K1_ZIw318P_9weN7tqzI/s1600/n4351.jpg" /></a></div>
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Source: <a href="http://oeis.org/">OEIS</a>Mathematical Association of Americahttp://www.blogger.com/profile/10559021045290192742noreply@blogger.com0tag:blogger.com,1999:blog-1050326564532544980.post-77671921055872864342014-12-09T03:00:00.000-05:002014-12-09T03:00:09.434-05:004347<b>4347</b> = 3 x 3 x 3 x 7 x 23.<br />
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<b>4347 </b>is a heptagonal number (<a href="http://oeis.org/A000566">A000566</a>). It is also a pentagonal number (<a href="http://oeis.org/A049452">A049452</a>).<br />
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<b>4347 </b>is the concatenation of the 27th and 28th primes (<a href="http://oeis.org/A045533">A045533</a>).<br />
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<b>4347</b> is a value of <i>n</i> for which 2<i>n</i> and 5<i>n</i> together use each of the digits 1 to 9 exactly once.<br />
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<b>4347</b> is the number of regions in a regular 63-gon that are octagons (<a href="http://oeis.org/A067155">A067155</a>).<br />
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<b>4347 </b>divides 22<sup>18</sup> - 1.<br />
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhQJBLemEe4nqdsBA-L3TksICiw94bn2vBK48u9mr8Q73RtQlU4Bjz9346NsnwRLHDNOuGoypE_Mt0eW1xndLOzQ0STnJGMVQ5vQUMLB3nbRxUq2BMujKCCAVu4tbbgYhd8FU7BY-KCZAM/s1600/n4347.jpg" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhQJBLemEe4nqdsBA-L3TksICiw94bn2vBK48u9mr8Q73RtQlU4Bjz9346NsnwRLHDNOuGoypE_Mt0eW1xndLOzQ0STnJGMVQ5vQUMLB3nbRxUq2BMujKCCAVu4tbbgYhd8FU7BY-KCZAM/s1600/n4347.jpg" height="72" width="200" /></a></div>
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Source: <a href="http://www.numbergossip.com/4347">Number Gossip</a>Mathematical Association of Americahttp://www.blogger.com/profile/10559021045290192742noreply@blogger.com0tag:blogger.com,1999:blog-1050326564532544980.post-62629142025496979242014-12-08T03:00:00.000-05:002014-12-08T03:00:05.862-05:005481<b>5481 </b>= 3 x 3 x 3 x 7 x 29.<br />
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<b>5481 </b>is 1956 in base 15 and 1569 in base 16.<br />
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<b>5481 </b>is the average of four consecutive odd squares (<a href="http://oeis.org/A173960">A173960</a>).<br />
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<b>5481</b> divides 88<sup>9</sup> - 1.<br />
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<div class="separator" style="clear: both; text-align: center;">
<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhHoGEJ2EOmbow_ZpYr7BvaEje9EQelh2Ci2aoxm2Ld2QPRicdpN7ahSFc-Zv7Ar-aSq25HtTw7UdRuxCYbkYktIi_QgBKfIdoFajzkOPhjxUgtLBBKI9a6Gy9XlWKokvVfq1mqQWQ0PFs/s1600/n5481.jpg" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhHoGEJ2EOmbow_ZpYr7BvaEje9EQelh2Ci2aoxm2Ld2QPRicdpN7ahSFc-Zv7Ar-aSq25HtTw7UdRuxCYbkYktIi_QgBKfIdoFajzkOPhjxUgtLBBKI9a6Gy9XlWKokvVfq1mqQWQ0PFs/s1600/n5481.jpg" height="61" width="200" /></a></div>
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Source: <a href="http://oeis.org/">OEIS</a>Mathematical Association of Americahttp://www.blogger.com/profile/10559021045290192742noreply@blogger.com0tag:blogger.com,1999:blog-1050326564532544980.post-5956096346269895232014-12-05T03:00:00.000-05:002014-12-05T03:00:04.675-05:004100<b>4100 </b>= 2 x 2 x 5 x 5 x 41.<br />
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<b>4100</b> is 5555 in base 9. It is 12121212 in base 3 (<a href="http://oeis.org/A037480">A037480</a> and <a href="http://oeis.org/A162216">A162216</a>).<br />
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<b>4100 </b>is a multiple of 5 with a digit sum of 5 (<a href="http://oeis.org/A069540">A069540</a>).<br />
<br />
<b>4100</b> has three representations as a sum of two squares (<a href="http://oeis.org/A025286">A025286</a>): <b>4100 </b>= 2<sup>2</sup> + 64<sup>2</sup> = 16<sup>2</sup> + 62<sup>2</sup> = 40<sup>2</sup> + 50<sup>2</sup>.<br />
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<b>4100 </b>divides 31<sup>10</sup> - 1.<br />
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjwH2evkE4un6WCFg8AZiTd4JSQv-0nVJBXkgIg9IsTTjlPlIBm9LTbvbfmefYUoQFl9u01rDy-VktXi4EndNs714YSY2eTjZq8KOXCCDht7SZnee6-oqIidqZmQcjpzzV_VlItVhyphenhyphenOhmg/s1600/n4100.jpg" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjwH2evkE4un6WCFg8AZiTd4JSQv-0nVJBXkgIg9IsTTjlPlIBm9LTbvbfmefYUoQFl9u01rDy-VktXi4EndNs714YSY2eTjZq8KOXCCDht7SZnee6-oqIidqZmQcjpzzV_VlItVhyphenhyphenOhmg/s1600/n4100.jpg" height="76" width="200" /></a></div>
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Source: <a href="http://www2.stetson.edu/~efriedma/numbers.html">What's Special About This Number?</a>Mathematical Association of Americahttp://www.blogger.com/profile/10559021045290192742noreply@blogger.com0tag:blogger.com,1999:blog-1050326564532544980.post-55248554248369114712014-12-04T03:00:00.000-05:002014-12-04T03:00:11.759-05:008242<b>8242 </b>= 2 x 13 x 317.<br />
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Concatenating <b>8242 </b>with 1 less than <b>8242 </b>produces a square (<a href="http://oeis.org/A054214">A054214</a> and <a href="http://oeis.org/A054215">A054215</a>): <b>8242</b>8241 = 9079<sup>2</sup>.<br />
<br />
The base 4 representation of <b>8242 </b>has 4 zeroes, 2 twos, and no ones (<a href="http://oeis.org/A045033">A045033</a> and <a href="http://oeis.org/A045059">A045059</a>): 2000302.<br />
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<b>8242</b> has two representations as a sum of two squares: <b>8242 </b>= 41<sup>2</sup> + 81<sup>2</sup> = 59<sup>2</sup> + 69<sup>2</sup>.<br />
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEim4aXpQ-Hg2S-rIgDE4C4San-_SiGHvDWAMJzZfoCYFPCw5SDmqrKXJOY8UoL4I0zNlBDT4vtYKufnGciBg9VKlFpfmEaZfv9UQoWxQcFknMI6Qnl3-bovJuxODGIyhAkMEoQMvK7Gjyw/s1600/n8242.jpg" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEim4aXpQ-Hg2S-rIgDE4C4San-_SiGHvDWAMJzZfoCYFPCw5SDmqrKXJOY8UoL4I0zNlBDT4vtYKufnGciBg9VKlFpfmEaZfv9UQoWxQcFknMI6Qnl3-bovJuxODGIyhAkMEoQMvK7Gjyw/s1600/n8242.jpg" height="68" width="200" /></a></div>
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Source: <a href="http://www2.stetson.edu/~efriedma/numbers.html">What's Special About This Number?</a>Mathematical Association of Americahttp://www.blogger.com/profile/10559021045290192742noreply@blogger.com0tag:blogger.com,1999:blog-1050326564532544980.post-58649627373959422962014-12-03T03:00:00.000-05:002014-12-03T03:00:01.916-05:001821<b>1821 </b>= 3 x 607.<br />
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<b>1821 </b>is a number that yields a prime whenever 1 is inserted anywhere in it, including at the beginning or end (<a href="http://oeis.org/A068679">A068679</a> and <a href="http://oeis.org/A216165">A216165</a>).<br />
<br />
<b>1821 </b>is a centered icosagonal number (<a href="http://oeis.org/A069133">A069133</a>). It is also a concentric decagonal number (<a href="http://oeis.org/A195142">A195142</a>).<br />
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<b>1821</b> is the number of primes less than the cube of 25 (<a href="http://oeis.org/A038098">A038098</a>).<br />
<br />
<b>1821 </b>is 2111110 in base 3. It is 130131 in base 4 and 3435 in base 8. <b>1821</b> is 24241 in base 5.<br />
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjX6EFK51JSSVNKLf-qCTFYcRXvoW2eUyASlvLvTX2sN_XJsp3T29b2C5JImpDAqPAGQR-FgNy7jhYgi_XVRveiUpm5a_s3FvoAnrjqfcyQWHTEBn5d_L9L_mJvXlyLSmUhnnUIMqzS5-c/s1600/n1821.jpg" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjX6EFK51JSSVNKLf-qCTFYcRXvoW2eUyASlvLvTX2sN_XJsp3T29b2C5JImpDAqPAGQR-FgNy7jhYgi_XVRveiUpm5a_s3FvoAnrjqfcyQWHTEBn5d_L9L_mJvXlyLSmUhnnUIMqzS5-c/s1600/n1821.jpg" height="89" width="200" /></a></div>
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Source: <a href="http://oeis.org/">OEIS</a>Mathematical Association of Americahttp://www.blogger.com/profile/10559021045290192742noreply@blogger.com0tag:blogger.com,1999:blog-1050326564532544980.post-29809993608506042552014-12-02T02:30:00.000-05:002014-12-02T02:30:01.425-05:003500<b>3500</b> = 2 x 2 x 5 x 5 x 5 x 7.<br />
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<b>3500</b> is a number that is the sum of two positive cubes and divisible by 7 (<a href="http://oeis.org/A101421">A101421</a>) and divisible by 5 (<a href="http://oeis.org/A224485">A224485</a>).<br />
<br />
<b>3500 </b>is the sum of three nonnegative cubes in more than one way (<a href="http://oeis.org/A001239">A001239</a>).<br />
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<b>3500 </b>is the number of rooted trees with 24 nodes with every leaf at height 3 (<a href="http://oeis.org/A048808">A048808</a>).<br />
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<b>3500</b> is a number <i>n</i> such that <i>n</i> and the square of <i>n</i> have only the digits 0, 1, 2, 3, and 5 in common (<a href="http://oeis.org/A136811">A136811</a>).<br />
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<b>3500 </b>divides 57<sup>4</sup> - 1.<br />
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgR5WyN9YJpeNWpj41A6jEMPa302CFqefx1pWP-hB2-ksreb5-ts3IBB9jlKdqpptiEO-_tl3Ye90k4JcFs_QMDhlVzftRUM2cywECi8yzyYhi4wmcnH7laeO3ULmUnBSiYdz8C5pWiVRE/s1600/n3500.jpg" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgR5WyN9YJpeNWpj41A6jEMPa302CFqefx1pWP-hB2-ksreb5-ts3IBB9jlKdqpptiEO-_tl3Ye90k4JcFs_QMDhlVzftRUM2cywECi8yzyYhi4wmcnH7laeO3ULmUnBSiYdz8C5pWiVRE/s1600/n3500.jpg" height="65" width="200" /></a></div>
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Source: <a href="http://oeis.org/">OEIS</a>Mathematical Association of Americahttp://www.blogger.com/profile/10559021045290192742noreply@blogger.com0tag:blogger.com,1999:blog-1050326564532544980.post-57025938260671797082014-12-01T02:30:00.000-05:002014-12-01T02:30:04.520-05:003048<b>3048 </b>= 2 x 2 x 2 x 3 x 127.<br />
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<b>3048</b> is a number that can be expressed as the difference of the squares of primes in just two distinct ways (<a href="http://oeis.org/A090788">A090788</a>).<br />
<br />
<b>3048 </b>is a number divisible by each of its digits, excluding 0 (<a href="http://oeis.org/A187398">A187398</a>).<br />
<br />
<b>3048 </b>is a number <i>n</i> such that <i>n</i> and the <i>n</i>th prime have only the digit 4 in common (<a href="http://oeis.org/A107935">A107935</a>).<br />
<br />
The <b>3048</b>th prime divides the <b>3048</b>th Fibonacci number (<a href="http://oeis.org/A075702">A075702</a>).<br />
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<b>3048 </b>divides 19<sup>6</sup> - 1.<br />
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgyhKUIziL5a3JpnwFQGcLVUiqnrD6CRoT6QEp5OSdJS8B1xWgyujBHbuugezKXrcUuEFBfAyzKLmwiy3-fZvBR-yIXRzzAcdsQO3EftXRxkapENks7ISS3_Qj_FxPWLzCUFl85UaKzZ7k/s1600/n3048.jpg" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgyhKUIziL5a3JpnwFQGcLVUiqnrD6CRoT6QEp5OSdJS8B1xWgyujBHbuugezKXrcUuEFBfAyzKLmwiy3-fZvBR-yIXRzzAcdsQO3EftXRxkapENks7ISS3_Qj_FxPWLzCUFl85UaKzZ7k/s1600/n3048.jpg" height="173" width="200" /></a></div>
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Source: <a href="http://oeis.org/">OEIS</a>Mathematical Association of Americahttp://www.blogger.com/profile/10559021045290192742noreply@blogger.com0tag:blogger.com,1999:blog-1050326564532544980.post-55365949522099487442014-11-26T02:30:00.000-05:002014-11-26T02:30:01.012-05:002445<b>2445</b> = 3 x 5 x 163.<br />
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<b>2445</b> is a <a href="http://mathworld.wolfram.com/TruncatedTetrahedralNumber.html">truncated tetrahedral number</a> (<a href="http://oeis.org/A005906">A005906</a>).<br />
<br />
<b>2445</b> is a number <i>n</i> such that <i>n</i>! has a square number of digits (<a href="http://oeis.org/A006488">A006488</a>).<br />
<br />
<b>2445 </b>is the sum of nine nonzero 6th powers (<a href="http://oeis.org/A003365">A003365</a>).<br />
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<b>2445 </b>is a lucky number that is divisible by the sum of its digits (<a href="http://oeis.org/A118564">A118564</a>).<br />
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<b>2445 </b>divides 59<sup>6</sup> - 1.<br />
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiLb-bmtlYppcu0kR6499XKXJ3PC_fgFJ33uP8SQtvu8P7Qh_bH9xKtkfqHub_y3Y-XezbLexxLeJfw4MAdHCtO7mGS0JNU6M_KrAnmFftPcRi-x20qFnbho0ueuaQq0gKsTuFPLRlqrU4/s1600/n2445.jpg" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiLb-bmtlYppcu0kR6499XKXJ3PC_fgFJ33uP8SQtvu8P7Qh_bH9xKtkfqHub_y3Y-XezbLexxLeJfw4MAdHCtO7mGS0JNU6M_KrAnmFftPcRi-x20qFnbho0ueuaQq0gKsTuFPLRlqrU4/s1600/n2445.jpg" /></a></div>
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Source: <a href="http://www2.stetson.edu/~efriedma/numbers.html">What's Special About This Number?</a>Mathematical Association of Americahttp://www.blogger.com/profile/10559021045290192742noreply@blogger.com0tag:blogger.com,1999:blog-1050326564532544980.post-38695172704263883972014-11-25T03:00:00.000-05:002014-11-25T03:00:09.537-05:001795<b>1795 </b>= 5 x 359.<br />
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<b>1795</b>, 1797, and 1799 are consecutive semiprimes (<a href="http://oeis.org/A133609">A133609</a>).<br />
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<b>1795</b> is the product of two distinct safe primes (<a href="http://oeis.org/A157352">A157352</a>).<br />
<br />
<b>1795 </b>has a base 5 representation (24140) that begins with its base 9 representation (2414).<br />
<br />
<b>1795</b> is the sum of 10 nonzero 8th powers (<a href="http://oeis.org/A003388">A003388</a>).<br />
<br />
<b>1795 </b>is a Smith semiprime (<a href="http://oeis.org/A098837">A098837</a>).<br />
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEitJz66jcxTk_0QYQilfaP10fCC7sdLmW_GwPgkmh6prFelkHmEp6SJdi7y0poixziaAoOsUXBxnXzkE2URVZ0OFGBdZ1wLppd4U-ElSeQe_5OayPO9W3BVC7Vfc-IggQwdfFhEeabZhXs/s1600/n1795.jpg" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEitJz66jcxTk_0QYQilfaP10fCC7sdLmW_GwPgkmh6prFelkHmEp6SJdi7y0poixziaAoOsUXBxnXzkE2URVZ0OFGBdZ1wLppd4U-ElSeQe_5OayPO9W3BVC7Vfc-IggQwdfFhEeabZhXs/s1600/n1795.jpg" height="81" width="200" /></a></div>
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Source: <a href="http://www2.stetson.edu/~efriedma/numbers.html">What's Special About This Number?</a>Mathematical Association of Americahttp://www.blogger.com/profile/10559021045290192742noreply@blogger.com0tag:blogger.com,1999:blog-1050326564532544980.post-45666732390729170672014-11-24T03:00:00.000-05:002014-11-24T03:00:11.137-05:001792<b>1792</b> = 2 x 2 x 2 x 2 x 2 x 2 x 2 x 2 x 7.<br />
<br />
<b>1792</b> is a <a href="http://www2.stetson.edu/~efriedma/mathmagic/0800.html">Friedman number</a> (<a href="http://oeis.org/A036057">A036057</a>).<br />
<br />
<b>1792 </b>is the maximum number of pieces obtained by slicing a bagel (torus) with 21 cuts (<a href="http://oeis.org/A003600">A003600</a>).<br />
<br />
<b>1792 </b>is a composite number such that the square root of the sum of squares of its prime factors is an integer (<a href="http://oeis.org/A134605">A134605</a>).<br />
<br />
<b>1792 </b>is the number of simple graphs with 9 vertices and two cycles (<a href="http://oeis.org/A112410">A112410</a>).<br />
<br />
<b>1792 </b>divides 97<sup>8</sup> - 1.<br />
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhbyOUz7X27OxgeT8cPuE8FC06DOw3LGvUOddXKkOUkaNUYWpAv6sAY3bfmsJaqoX4ZD_yPAUx4i9KqoQHu8alCoRieute2DM7IW8VvW_zqHqo6nEquC4DvFFI6gRgnikOvSvGEc6qrksQ/s1600/n1792.jpg" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhbyOUz7X27OxgeT8cPuE8FC06DOw3LGvUOddXKkOUkaNUYWpAv6sAY3bfmsJaqoX4ZD_yPAUx4i9KqoQHu8alCoRieute2DM7IW8VvW_zqHqo6nEquC4DvFFI6gRgnikOvSvGEc6qrksQ/s1600/n1792.jpg" height="77" width="200" /></a></div>
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Source: <a href="http://oeis.org/">OEIS</a>Mathematical Association of Americahttp://www.blogger.com/profile/10559021045290192742noreply@blogger.com0tag:blogger.com,1999:blog-1050326564532544980.post-29384317748848091472014-11-21T03:00:00.000-05:002014-11-21T03:00:07.981-05:005101<b>5101</b> is a prime number.<br />
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5099 and <b>5101 </b>form a twin prime pair.<br />
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<b>5101 </b>is the initial prime in a set of four consecutive primes with common difference 6 (<a href="http://oeis.org/A033451">A033451</a>).<br />
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<b>5101</b> is a prime formed from merging four successive digits in the decimal expansion of <i>e</i> (<a href="http://oeis.org/A104845">A104845</a>).<br />
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<b>5101 </b>is a prime whose sum of digits is 7 (<a href="http://oeis.org/A062337">A062337</a>).<br />
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<b>5101 </b>is a centered 17-gonal number (<a href="http://oeis.org/A069130">A069130</a>).<br />
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<b>5101 </b>has a representation as a sum of two squares: <b>5101 </b>= 50<sup>2</sup> + 51<sup>2</sup>. <b>5101 </b>is a prime that is the sum of at least two consecutive squares (<a href="http://oeis.org/A163251">A163251</a>).<br />
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<b>5101 </b>is the hypotenuse of a primitive Pythagorean triple: <b>5101</b><sup>2</sup> = 101<sup>2</sup> + 5100<sup>2</sup>.<br />
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<b>5101 </b>divides 46<sup>20</sup> - 1.<br />
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiCuiRiMWZh8LG_xq5wAiB82_jPDTDJ8zNcL8iKNIQaPnIicm27xO26OrrySTHhBAZZQrvWVw-mHGjhYsVnQwGulL_w7sdA9hxSepS1eo-76YaWGxPQfHDebQ5kwZAwXRDSCOVYfVvwY8I/s1600/n5101.jpg" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiCuiRiMWZh8LG_xq5wAiB82_jPDTDJ8zNcL8iKNIQaPnIicm27xO26OrrySTHhBAZZQrvWVw-mHGjhYsVnQwGulL_w7sdA9hxSepS1eo-76YaWGxPQfHDebQ5kwZAwXRDSCOVYfVvwY8I/s1600/n5101.jpg" height="58" width="200" /></a></div>
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Source: <a href="http://oeis.org/">OEIS</a>Mathematical Association of Americahttp://www.blogger.com/profile/10559021045290192742noreply@blogger.com0tag:blogger.com,1999:blog-1050326564532544980.post-29320266018958434882014-11-20T03:00:00.000-05:002014-11-20T03:00:08.794-05:003001<b>3001 </b>is a prime number.<br />
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2999 and <b>3001</b> form a twin prime pair.<br />
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<b>3001</b> is a prime whose digit sum is 4 (<a href="http://oeis.org/A062339">A062339</a>). It is the largest 4-digit prime with minimum digit sum (<a href="http://oeis.org/A069664">A069664</a>).<br />
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<b>3001 </b>is a centered decagonal number (<a href="http://oeis.org/A062786">A062786</a>).<br />
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<b>3001</b> is a prime that can be expressed as the sum of distinct powers of 3 (<a href="http://oeis.org/A077717">A077717</a>).<br />
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<b>3001 </b>is 1/24 of the 24th <a href="http://mathworld.wolfram.com/FibonacciNumber.html">Fibonacci number</a>.<br />
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<b>3001</b> has a representation as a sum of two squares: <b>3001 </b>= 20<sup>2</sup> + 51<sup>2</sup>.<br />
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<b>3001 </b>is the hypotenuse of a primitive Pythagorean triple: <b>3001</b><sup>2</sup> = 2040<sup>2</sup> + 2201<sup>2</sup>.<br />
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<b>3001</b> divides 20<sup>15</sup> - 1.<br />
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjMcZNtK7K5k-yDFJ0t8crdMLfq7GN6XftTHpa0e0c2pbf6dQa5EGYPa6IBIslZ872LDN-Qv5bH2qMduWKtJcs1c5p2UW6ylBYb_1EpyB7E4rEivHenU_f_o1Rmga0lQv6DNwbfig9xils/s1600/n3001.jpg" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjMcZNtK7K5k-yDFJ0t8crdMLfq7GN6XftTHpa0e0c2pbf6dQa5EGYPa6IBIslZ872LDN-Qv5bH2qMduWKtJcs1c5p2UW6ylBYb_1EpyB7E4rEivHenU_f_o1Rmga0lQv6DNwbfig9xils/s1600/n3001.jpg" height="83" width="200" /></a></div>
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<a href="http://en.wikipedia.org/wiki/Arthur_C._Clarke">Arthur C. Clarke</a> wrote a book titled <i><a href="http://en.wikipedia.org/wiki/3001:_The_Final_Odyssey"><b>3001</b>: The Final Odyssey</a></i>.<br />
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Source: <a href="http://primes.utm.edu/curios/page.php/3001.html">Prime Curios!</a>Mathematical Association of Americahttp://www.blogger.com/profile/10559021045290192742noreply@blogger.com0tag:blogger.com,1999:blog-1050326564532544980.post-46237279743351443982014-11-19T03:00:00.000-05:002014-11-19T03:00:17.800-05:001785<b>1785 </b>= 3 x 5 x 7 x 17.<br />
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<b>1785</b> is a multiple of 7 such that its digit sum is divisible by 7 (<a href="http://oeis.org/A216994">A216994</a>).<br />
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<b>1785</b> is a <a href="http://mathworld.wolfram.com/SquarePyramidalNumber.html">square pyramidal number</a> (<a href="http://oeis.org/A000330">A000330</a>). It is also a pentadecagonal number (<a href="http://oeis.org/A051867">A051867</a>).<br />
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<b>1785 </b>is palindromic in base 5: 123321.<br />
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<b>1785 </b>is the sum of five positive fifth powers (<a href="http://oeis.org/A003350">A00335</a>0).<br />
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<b>1785 </b>divides 13<sup>4</sup> - 1.<br />
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Source: <a href="http://oeis.org/">OEIS</a>Mathematical Association of Americahttp://www.blogger.com/profile/10559021045290192742noreply@blogger.com0