OFFSET
0,3
LINKS
Seiichi Manyama, Table of n, a(n) for n = 0..1000
FORMULA
G.f.: Product_{n>=1} (1 - x^n)^(n^2).
a(n) = -(1/n)*Sum_{k=1..n} sigma_3(k)*a(n-k).
MATHEMATICA
a[n_] := If[n<1, 1, -(1/n) * Sum[DivisorSigma[3, k] a[n - k], {k, n}]]; Table[a[n], {n, 0, 35}] (* Indranil Ghosh, Mar 16 2017 *)
PROG
(PARI) a(n) = if(n<1, 1, -(1/n) * sum(k=1, n, sigma(k, 3) * a(n - k)));
for(n=0, 35, print1(a(n), ", ")) \\ Indranil Ghosh, Mar 16 2017
(SageMath) # uses[EulerTransform from A166861]
b = EulerTransform(lambda n: -n^2)
print([b(n) for n in range(36)]) # Peter Luschny, Nov 11 2020
CROSSREFS
KEYWORD
sign
AUTHOR
Seiichi Manyama, Mar 04 2017
STATUS
approved