OFFSET
0,5
FORMULA
E.g.f.: Sum_{k>=1} (1 - exp(-k*x))^k / k^3.
Sum_{k>=0} a(k+2) * x^k/k! = Sum_{k>=0} k * (1 - exp(-k*x))^k.
PROG
(PARI) a(n) = sum(k=1, n, (-1)^(n-k)*k!*k^(n-3)*stirling(n, k, 2));
CROSSREFS
KEYWORD
nonn
AUTHOR
Seiichi Manyama, Jun 20 2024
STATUS
approved