OFFSET
1,2
FORMULA
If p is prime, a(p) = p + (p-1)!.
E.g.f.: Sum_{k>0} x^k/k * exp(x^k).
PROG
(PARI) a(n) = (n-1)!*sumdiv(n, d, d/(d-1)!);
(PARI) my(N=30, x='x+O('x^N)); Vec(serlaplace(sum(k=1, N, x^k/k*exp(x^k))))
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
Seiichi Manyama, Feb 23 2024
STATUS
approved