OFFSET
0,3
FORMULA
E.g.f.: Sum_{k>=1} (exp(k*x) - 1)^k / k^2.
PROG
(PARI) a(n) = sum(k=1, n, k!*k^(n-2)*stirling(n, k, 2));
CROSSREFS
KEYWORD
nonn
AUTHOR
Seiichi Manyama, Jun 20 2024
STATUS
approved