OFFSET
0,3
MATHEMATICA
a[0] = 1; a[n_] := Sum[k^n * (n-k)! * Binomial[n, k]^2, {k, 0, n}]; Array[a, 16, 0] (* Amiram Eldar, Feb 06 2021 *)
PROG
(PARI) a(n) = sum(k=0, n, k^n*(n-k)!*binomial(n, k)^2);
CROSSREFS
KEYWORD
nonn
AUTHOR
Seiichi Manyama, Feb 06 2021
STATUS
approved