OFFSET
0,4
FORMULA
G.f.: exp(-Sum_{k>=1} sigma(k)*(x*(1-x))^k/k).
MATHEMATICA
m = 41; CoefficientList[Series[Product[(1 - (x*(1 - x))^k), {k, 1, m}], {x, 0, m}], x] (* Amiram Eldar, May 07 2021 *)
PROG
(PARI) N=66; x='x+O('x^N); Vec(prod(k=1, N, 1-(x*(1-x))^k))
(PARI) N=66; x='x+O('x^N); Vec(exp(-sum(k=1, N, sigma(k)*(x*(1-x))^k/k)))
CROSSREFS
KEYWORD
sign
AUTHOR
Seiichi Manyama, Sep 21 2019
STATUS
approved