OFFSET
0,3
FORMULA
a(n) = Sum_{k=0..floor(n/2)} (2*k)! * (n+k+1)^(k-1) * Stirling2(n,2*k)/k!.
PROG
(PARI) a(n) = sum(k=0, n\2, (2*k)!*(n+k+1)^(k-1)*stirling(n, 2*k, 2)/k!);
CROSSREFS
KEYWORD
nonn
AUTHOR
Seiichi Manyama, Sep 11 2022
STATUS
approved