OFFSET
0,3
LINKS
Winston de Greef, Table of n, a(n) for n = 0..385
FORMULA
a(n) = Sum_{k=1..n} k^k * binomial(n-1,k-1) for n > 0.
a(n) ~ exp(exp(-1)) * n^n. - Vaclav Kotesovec, Jul 05 2022
MATHEMATICA
Join[{1}, Table[Sum[k^k * Binomial[n-1, k-1], {k, 1, n}], {n, 1, 20}]] (* Vaclav Kotesovec, Jul 05 2022 *)
PROG
(PARI) my(N=20, x='x+O('x^N)); Vec(sum(k=0, N, (k*x/(1-x))^k))
(PARI) a(n) = if(n==0, 1, sum(k=1, n, k^k*binomial(n-1, k-1)));
CROSSREFS
KEYWORD
nonn
AUTHOR
Seiichi Manyama, Jul 04 2022
STATUS
approved