OFFSET
0,2
LINKS
Seiichi Manyama, Table of n, a(n) for n = 0..10000
MATHEMATICA
With[{nmax=80}, CoefficientList[Series[Product[((1-q^k)/(1+q^k) )^DivisorSigma[1, k], {k, 1, nmax+2}], {q, 0, nmax}], q]] (* G. C. Greubel, Oct 29 2018 *)
PROG
(PARI) N=99; x='x+O('x^N); Vec(prod(k=1, N, ((1-x^k)/(1+x^k))^sigma(k)))
(Magma) m:=80; R<q>:=PowerSeriesRing(Rationals(), m); Coefficients(R!( (&*[((1-q^k)/(1+q^k))^DivisorSigma(1, k): k in [1..(m+2)]]) )); // G. C. Greubel, Oct 29 2018
CROSSREFS
KEYWORD
sign
AUTHOR
Seiichi Manyama, Oct 25 2018
STATUS
approved