OFFSET
0,2
FORMULA
E.g.f.: Sum_{k>=0} exp(k^k * x) * x^k/k!.
a(n) = Sum_{k=0..n} k^(k*(n-k)) * binomial(n,k).
PROG
(PARI) my(N=20, x='x+O('x^N)); Vec(sum(k=0, N, x^k/(1-k^k*x)^(k+1)))
(PARI) my(N=20, x='x+O('x^N)); Vec(serlaplace(sum(k=0, N, exp(k^k*x)*x^k/k!)))
(PARI) a(n) = sum(k=0, n, k^(k*(n-k))*binomial(n, k));
CROSSREFS
KEYWORD
nonn
AUTHOR
Seiichi Manyama, Jul 03 2022
STATUS
approved