Monday, February 2, 2009

19

19 is a prime number.

19 has a unique representation as a sum of three squares: 19 = 12 + 32 + 32.

19 is the fourth centered triangular number.


19 is the largest prime number that is a palindrome in Roman numerals (XIX).

17 and 19 form a twin prime pair.


Go is played by two players who alternately place black and white pieces on the vacant intersections of a grid of 19 by 19 lines.

Source:
Number Gossip

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