OFFSET
0,3
FORMULA
Sum_{n>=0} a(n) * x^n / (n!)^4 = 1 / (1 + polylog(4,x)).
MATHEMATICA
a[0] = 1; a[n_] := a[n] = -(n!)^4 Sum[a[k]/(k! (n - k))^4, {k, 0, n - 1}]; Table[a[n], {n, 0, 13}]
nmax = 13; CoefficientList[Series[1/(1 + PolyLog[4, x]), {x, 0, nmax}], x] Range[0, nmax]!^4
PROG
(PARI) a(n)={n!^4*polcoef(1/(1 + polylog(4, x + O(x*x^n))), n)} \\ Andrew Howroyd, Sep 15 2020
CROSSREFS
KEYWORD
sign
AUTHOR
Ilya Gutkovskiy, Sep 15 2020
STATUS
approved