OFFSET
0,3
LINKS
Seiichi Manyama, Table of n, a(n) for n = 0..7039
FORMULA
Convolution inverse of A288415.
a(0) = 1, a(n) = -(1/n)*Sum_{k=1..n} A288420(k)*a(n-k) for n > 0.
G.f.: exp(-Sum_{k>=1} sigma_4(k)*x^k/(k*(1 - x^(2*k)))). - Ilya Gutkovskiy, Oct 29 2018
MAPLE
with(numtheory): seq(coeff(series(mul(1/(1+x^k)^(sigma[3](k)), k=1..n), x, n+1), x, n), n = 0 .. 30); # Muniru A Asiru, Oct 31 2018
MATHEMATICA
nmax = 40; CoefficientList[Series[Product[1/(1+x^k)^DivisorSigma[3, k], {k, 1, nmax}], {x, 0, nmax}], x] (* Vaclav Kotesovec, Jun 09 2017 *)
PROG
(PARI) m=40; x='x+O('x^m); Vec(prod(k=1, m, 1/(1+x^k)^sigma(k, 3))) \\ G. C. Greubel, Oct 30 2018
(Magma) m:=40; R<q>:=PowerSeriesRing(Rationals(), m); Coefficients(R! ( (&*[1/(1+q^k)^DivisorSigma(3, k): k in [1..m]]) )); // G. C. Greubel, Oct 30 2018
CROSSREFS
KEYWORD
sign
AUTHOR
Seiichi Manyama, Jun 09 2017
STATUS
approved