A022713 Expansion of Product_{m>=1} (1+m*q^m)^-21.

1, -21, 189, -952, 3087, -8400, 27503, -92907, 246981, -588490, 1649823, -4645179, 10989769, -25476717, 65615424, -161705810, 363998754, -834169539, 1973130271, -4510112565, 9969930495, -22054706773

Offset: 0

Author

N. J. A. Sloane

Keywords

• sign

Links

• G. C. Greubel, Table of n, a(n) for n = 0..1000

Programs

Mathematica

With[{nmax = 50}, CoefficientList[Series[Product[(1 + k*q^k)^-21, {k, 1, nmax}], {q, 0, nmax}], q]] (* G. C. Greubel, Jul 20 2018 *)

PARI

m=50; q='q+O('q^m); Vec(prod(n=1,m,(1+n*q^n)^-21)) \\ G. C. Greubel, Jul 20 2018