OFFSET
0,2
FORMULA
a(n) = n! * [x^n] exp( -x * (exp(n * x) + 1) ).
a(n) = [x^n] Sum_{k>=0} (-x)^k / (1 - (n*k-1)*x)^(k+1).
PROG
(PARI) a(n) = sum(k=0, n, (-1)^k*(k*n-1)^(n-k)*binomial(n, k));
CROSSREFS
KEYWORD
sign
AUTHOR
Seiichi Manyama, Aug 29 2022
STATUS
approved