A176837 Number of pairs (a, b) of positive integers with a < b such that both a^2 - nb and b^2 - na are squares.

0, 0, 2, 1, 4, 2, 6, 5, 9, 4, 8, 13, 12, 6, 21, 18, 14, 9, 14, 28, 27

Offset: 1

Author

Jens Voß, Apr 27 2010

Keywords

• nonn

Examples

			A176837(3) = 2 because the pairs (5, 8) and (7, 11) have the specified property: 5^2 - 3*8 = 1^2, 8^2 - 3*5 = 7^2; 7^2 - 3*11 = 4^2, 11^2 - 3*7 = 10^2.
		

Crossrefs

A176837(n) = A176836(n) - A176835(n)