OFFSET
0,4
COMMENTS
Convolution inverse of A261049.
LINKS
Eric Weisstein's World of Mathematics, Partition Function P
FORMULA
G.f.: Product_{k>=1} 1/(1 + x^k)^A000041(k).
MATHEMATICA
nmax = 43; CoefficientList[Series[Product[1/(1 + x^k)^PartitionsP[k], {k, 1, nmax}], {x, 0, nmax}], x]
a[n_] := a[n] = If[n == 0, 1, Sum[Sum[(-1)^(k/d) d PartitionsP[d], {d, Divisors[k]}] a[n - k], {k, 1, n}]/n]; Table[a[n], {n, 0, 43}]
CROSSREFS
KEYWORD
sign
AUTHOR
Ilya Gutkovskiy, May 18 2018
STATUS
approved