OFFSET
0,2
LINKS
Seiichi Manyama, Table of n, a(n) for n = 0..29
FORMULA
a(n) = [x^n] Sum_{k>=0} (k!)^(n+1) * x^k/(1 - x)^(k+1).
a(n) = n! * [x^n] exp(x) * Sum_{k>=0} (k!)^n * x^k.
MATHEMATICA
a[n_] := Sum[(k!)^(n+1) * Binomial[n, k], {k, 0, n} ]; Array[a, 10, 0] (* Amiram Eldar, May 04 2021 *)
PROG
(PARI) a(n) = sum(k=0, n, k!^(n+1)*binomial(n, k));
CROSSREFS
KEYWORD
nonn
AUTHOR
Seiichi Manyama, May 04 2021
STATUS
approved