Monday, June 10, 2013

1580

1580 = 2 x 2 x 5 x 79.

1580 is a divisor of 2312 - 1.

1580 is a number n such that 1 + n + n3 + n5 + n7 + n9 + n11 + n13 + n15 + n17 + n19 + n21 + n23 is prime (A124181).

1580 is the number of regions in a 20-sided regular polygon that are four-sided polygons (4-gons) (A067151).

1580 is the number of partitions of 332 into distinct squares (A030273).


Source: On-Line Encyclopedia of Integer Sequences

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