OFFSET
0,3
FORMULA
a(n) = n!*Sum_{k=0..n} (-1)^(n-k)*(n*(n-k))^k/k!.
a(n) = Sum_{k=0..n} (-1)^k*k!*(n*k)^(n-k)*binomial(n,k).
MATHEMATICA
Table[n! SeriesCoefficient[1/(1 + x Exp[n x]), {x, 0, n}], {n, 0, 18}]
Join[{1}, Table[n! Sum[(-1)^(n - k) (n (n - k))^k/k!, {k, 0, n}], {n, 18}]]
Join[{1}, Table[Sum[(-1)^k k! (n k)^(n - k) Binomial[n, k], {k, 0, n}], {n, 18}]]
CROSSREFS
KEYWORD
sign
AUTHOR
Ilya Gutkovskiy, Apr 07 2018
STATUS
approved