OFFSET
0,2
COMMENTS
Convolution inverse of A145519.
FORMULA
G.f.: Product_{k>=1} (1 - A000040(k)*x^k).
MATHEMATICA
nmax = 40; CoefficientList[Series[Product[(1 - Prime[k] x^k), {k, 1, nmax}], {x, 0, nmax}], x]
a[n_] := a[n] = If[n == 0, 1, Sum[-Sum[d Prime[d]^(k/d), {d, Divisors[k]}] a[n - k], {k, 1, n}]/n]; Table[a[n], {n, 0, 40}]
CROSSREFS
KEYWORD
sign
AUTHOR
Ilya Gutkovskiy, May 18 2018
STATUS
approved