A292497 Number of solutions to 1^2 +- 3^2 +- 5^2 +- 7^2 +- ... +- (4*n-1)^2 = 0.

1, 0, 0, 0, 1, 0, 6, 0, 20, 5, 258, 62, 2510, 914, 24285, 16403, 263945, 222240, 3068971, 3241157, 35286928, 46638022, 426740187, 650095127, 5330192371, 9185814630, 67064945191, 129902075662, 864443143567, 1833530501143, 11336065334984, 25990268638322

Offset: 0

Author

Seiichi Manyama, Sep 17 2017

Keywords

• nonn

Links

• Seiichi Manyama, Table of n, a(n) for n = 0..100

Crossrefs

Cf. A083527, A156700, A292496.

Formula

For n>0 constant term in the expansion of 1/2 * Product_{k=1..2*n} (x^(2*k-1)^2+1/x^(2*k-1)^2).

a(n) = A292496(n)/2 for n>0.