OFFSET
0,3
LINKS
Seiichi Manyama, Table of n, a(n) for n = 0..214
FORMULA
a(n) ~ exp(exp(-2)/2) * n^(2*n).
E.g.f.: Sum_{k>=0} (k^2 * (exp(x) - 1))^k / k!. - Seiichi Manyama, Feb 04 2022
MATHEMATICA
Join[{1}, Table[Sum[k^(2*k)*StirlingS2[n, k], {k, 1, n}], {n, 1, 20}]]
PROG
(PARI) my(N=20, x='x+O('x^N)); Vec(serlaplace(sum(k=0, N, (k^2*(exp(x)-1))^k/k!))) \\ Seiichi Manyama, Feb 04 2022
CROSSREFS
KEYWORD
nonn
AUTHOR
Vaclav Kotesovec, May 31 2019
STATUS
approved