OFFSET
0,3
LINKS
Alois P. Heinz, Table of n, a(n) for n = 0..383
FORMULA
a(n) = T(n,4), T(n,k) = Sum_{j=0..n} Stirling2(n,j) * T(j,k-1), k>1, T(n,0) = n!.
MAPLE
b:= proc(n, m, t) option remember; `if`(n=0, `if`(t=1, m!,
b(m, 0, t-1)), m*b(n-1, m, t)+b(n-1, m+1, t))
end:
a:= n-> b(n, 0, 4):
seq(a(n), n=0..20); # Alois P. Heinz, May 12 2023
PROG
(PARI) my(N=20, x='x+O('x^N)); Vec(serlaplace(1/(2-exp(exp(exp(exp(x)-1)-1)-1))))
CROSSREFS
KEYWORD
nonn
AUTHOR
Seiichi Manyama, May 12 2023
STATUS
approved