A281266 Main diagonal of A279928.

1, -1, -1, -1, 23, -51, 35, -197, 1367, -3889, 7649, -26258, 112739, -350676, 939623, -3063201, 11022167, -35276497, 106320311, -344831533, 1164544273, -3765456206, 11890410454, -38631658591, 127610160227, -414671018176, 1335126443260, -4348160271568

Offset: 0

Author

Seiichi Manyama, Apr 13 2017

Keywords

• sign

Links

• Vaclav Kotesovec, Table of n, a(n) for n = 0..1000 (terms 0..100 from Seiichi Manyama)

Crossrefs

Cf. A255672, A279928.

Programs

Mathematica

nmax = 30; Table[SeriesCoefficient[Product[1/(1 + x^k)^(m*k), {k, 1, m}], {x, 0, m}], {m, 0, nmax}] (* Vaclav Kotesovec, Apr 17 2017 *)

Formula

a(n) ~ (-1)^n * c * d^n / sqrt(n), where d = 3.31585574856163070436... and c = 0.20250147602443379616... - Vaclav Kotesovec, Apr 17 2017

a(n) = [x^n] exp(n*Sum_{k>=1} (-1)^k*x^k/(k*(1 - x^k)^2)). - Ilya Gutkovskiy, May 30 2018