OFFSET
0,5
COMMENTS
Invert transform of A001221.
LINKS
Alois P. Heinz, Table of n, a(n) for n = 0..2000
N. J. A. Sloane, Transforms
FORMULA
G.f.: 1/(1 - Sum_{k>=2} A001221(k)*x^k).
MAPLE
a:= proc(n) option remember; `if`(n=0, 1,
add(a(n-i)*nops(ifactors(i)[2]), i=1..n))
end:
seq(a(n), n=0..42); # Alois P. Heinz, Feb 11 2021
MATHEMATICA
nmax = 42; CoefficientList[Series[1/(1 - Sum[x^Prime[k]/(1 - x^Prime[k]), {k, 1, nmax}]), {x, 0, nmax}], x]
nmax = 42; CoefficientList[Series[1/(1 - Sum[PrimeNu[k] x^k, {k, 2, nmax}]), {x, 0, nmax}], x]
a[0] = 1; a[n_] := a[n] = Sum[PrimeNu[k] a[n - k], {k, 1, n}]; Table[a[n], {n, 0, 42}]
CROSSREFS
KEYWORD
nonn
AUTHOR
Ilya Gutkovskiy, Mar 11 2018
STATUS
approved