OFFSET
0,2
FORMULA
a(n) ~ 2^n * n^n. - Vaclav Kotesovec, Dec 06 2021
MATHEMATICA
a[0] = 1; a[n_] := Sum[(k + n)^k, {k, 0, n}]; Array[a, 18, 0] (* Amiram Eldar, Dec 05 2021 *)
PROG
(PARI) a(n) = sum(k=0, n, (k+n)^k);
CROSSREFS
KEYWORD
nonn
AUTHOR
Seiichi Manyama, Dec 05 2021
STATUS
approved