OFFSET
0,3
FORMULA
a(n) = (n!)^3 * [x^n] exp(-Sum_{k>=1} x^k / (k!)^3).
MATHEMATICA
a[0] = 1; a[n_] := a[n] = -(1/n) Sum[Binomial[n, k]^3 (n - k) a[k], {k, 0, n - 1}]; Table[a[n], {n, 0, 17}]
nmax = 17; CoefficientList[Series[Exp[-Sum[x^k/(k!)^3, {k, 1, nmax}]], {x, 0, nmax}], x] Range[0, nmax]!^3
CROSSREFS
KEYWORD
sign
AUTHOR
Ilya Gutkovskiy, Jul 12 2020
STATUS
approved