OFFSET
0,3
FORMULA
a(n) ~ exp(-1/2) * n!^2. - Vaclav Kotesovec, Jul 05 2021
MATHEMATICA
Table[Sum[Abs[StirlingS1[n+1, k+1]](-1)^(n-k)k!^2, {k, 0, n}], {n, 0, 100}]
PROG
(Maxima) makelist(sum(abs(stirling1(n+1, k+1))*(-1)^(n-k)*k!^2, k, 0, n), n, 0, 24);
CROSSREFS
KEYWORD
nonn
AUTHOR
Emanuele Munarini, Jul 04 2011
STATUS
approved