OFFSET
0,3
LINKS
Seiichi Manyama, Table of n, a(n) for n = 0..449
FORMULA
a(n) ~ Pi * n^(n+1) / exp(n).
a(n) ~ sqrt(Pi*n/2) * n!.
MATHEMATICA
Table[Sum[k! * k^(n-k), {k, 0, n}], {n, 1, 20}]
PROG
(PARI) a(n) = sum(k=0, n, k!*k^(n-k)); \\ Seiichi Manyama, Dec 31 2023
CROSSREFS
KEYWORD
nonn
AUTHOR
Vaclav Kotesovec, Nov 01 2023
EXTENSIONS
a(0)=1 prepended by Seiichi Manyama, Dec 31 2023
STATUS
approved