OFFSET
0,3
LINKS
Eric Weisstein's World of Mathematics, Lambert W-Function.
FORMULA
a(0) = 0; a(n) = n*a(n-1) + n^n.
a(n) = A277506(n) - n!.
E.g.f.: -1/( (1 + 1/LambertW(-x)) * (1 - x) ).
a(n) ~ n^n / (1 - exp(-1)). - Vaclav Kotesovec, Jul 22 2024
MAPLE
a:= proc(n) a(n):= n*a(n-1) + n^n end: a(0):= 0:
seq(a(n), n=0..23); # Alois P. Heinz, Jul 22 2024
PROG
(PARI) a(n) = n!*sum(k=1, n, k^k/k!);
CROSSREFS
KEYWORD
nonn
AUTHOR
Seiichi Manyama, Jul 22 2024
STATUS
approved