OFFSET
0,5
LINKS
Seiichi Manyama, Table of n, a(n) for n = 0..418
FORMULA
a(0) = 1; a(n) = 24 * Sum_{k=1..n} binomial(n,k) * |Stirling1(k,4)| * a(n-k).
a(n) = Sum_{k=0..floor(n/4)} (4*k)! * |Stirling1(n,4*k)|.
a(n) ~ sqrt(2*Pi) * n^(n + 1/2) / (4 * (exp(1) - 1)^(n+1)). - Vaclav Kotesovec, May 07 2022
MATHEMATICA
With[{nn=20}, CoefficientList[Series[1/(1-Log[1-x]^4), {x, 0, nn}], x] Range[0, nn]!] (* Harvey P. Dale, Jul 13 2024 *)
PROG
(PARI) my(N=30, x='x+O('x^N)); Vec(serlaplace(1/(1-log(1-x)^4)))
(PARI) a_vector(n) = my(v=vector(n+1)); v[1]=1; for(i=1, n, v[i+1]=24*sum(j=1, i, binomial(i, j)*abs(stirling(j, 4, 1))*v[i-j+1])); v;
(PARI) a(n) = sum(k=0, n\4, (4*k)!*abs(stirling(n, 4*k, 1)));
CROSSREFS
KEYWORD
nonn
AUTHOR
Seiichi Manyama, May 06 2022
STATUS
approved