OFFSET
0,3
LINKS
Alois P. Heinz, Table of n, a(n) for n = 0..400
Eric Weisstein's World of Mathematics, Lambert W-Function.
FORMULA
E.g.f.: 1/(1 + LambertW(exp(x) - 1)), where LambertW() is the Lambert W-function.
a(n) ~ (-1)^n * n^n / (sqrt(exp(1)-1) * (1 - log(exp(1)-1))^(n + 1/2) * exp(n)). - Vaclav Kotesovec, Feb 05 2022
MAPLE
b:= proc(n, m) option remember; `if`(n=0,
(-m)^m, m*b(n-1, m)+b(n-1, m+1))
end:
a:= n-> b(n, 0):
seq(a(n), n=0..20); # Alois P. Heinz, Jul 17 2022
MATHEMATICA
Table[Sum[(-1)^k * k^k * StirlingS2[n, k], {k, 1, n}], {n, 0, 20}] (* Vaclav Kotesovec, Feb 05 2022 *)
PROG
(PARI) a(n) = sum(k=0, n, (-k)^k*stirling(n, k, 2));
(PARI) my(N=40, x='x+O('x^N)); Vec(serlaplace(1/(1+lambertw(exp(x)-1))))
CROSSREFS
KEYWORD
sign
AUTHOR
Seiichi Manyama, Feb 05 2022
STATUS
approved