OFFSET
1,2
FORMULA
a(n) = Sum_{k=1..n} A087906(k) * binomial(n,k).
E.g.f.: exp(x) * Sum_{k>0} (exp(x^k) - 1)/k.
E.g.f.: -exp(x) * Sum_{k>0} log(1-x^k)/k!.
PROG
(PARI) a087906(n) = n!*sumdiv(n, d, 1/(d*(n/d)!));
a(n) = sum(k=1, n, a087906(k)*binomial(n, k));
(PARI) my(N=30, x='x+O('x^N)); Vec(serlaplace(exp(x)*sum(k=1, N, (exp(x^k)-1)/k)))
(PARI) my(N=30, x='x+O('x^N)); Vec(serlaplace(-exp(x)*sum(k=1, N, log(1-x^k)/k!)))
CROSSREFS
KEYWORD
nonn
AUTHOR
Seiichi Manyama, Aug 15 2022
STATUS
approved