A285287 Expansion of Product_{k>=0} 1/(1 + x^(4*k+1))^(4*k+1).

1, -1, 1, -1, 1, -6, 6, -6, 6, -15, 30, -30, 30, -43, 88, -123, 123, -140, 250, -385, 455, -476, 678, -1098, 1413, -1564, 1913, -2918, 4048, -4707, 5452, -7572, 10747, -13265, 15195, -19534, 27349, -35146, 41042, -50011, 67596, -88897, 106519, -126635, 164230

Offset: 0

Author

Seiichi Manyama, Apr 16 2017

Keywords

• sign

Links

• Seiichi Manyama, Table of n, a(n) for n = 0..10000

Crossrefs

Product_{k>=0} 1/(1 + x^(m*k+1))^(m*k+1): A284628 (m=2), A285286 (m=3), this sequence (m=4).

Cf. A285048, A285288.

Programs

Mathematica

nmax = 50; CoefficientList[Series[Product[1/(1 + x^(4*k-3))^(4*k-3), {k,1,nmax}], {x,0,nmax}], x] (* Vaclav Kotesovec, Apr 16 2017 *)

Formula

a(n) = (-1)^n * A285048(n).