OFFSET
0,3
LINKS
Alois P. Heinz, Table of n, a(n) for n = 0..246
FORMULA
a(n) = T(n,n), T(n,k) = Sum_{j=0..n} Stirling2(n,j) * T(j,k-1), k>1, T(n,0) = n!.
MAPLE
b:= proc(n, t, m) option remember; `if`(n=0, `if`(t<2, m!,
b(m, t-1, 0)), m*b(n-1, t, m)+b(n-1, t, m+1))
end:
a:= n-> b(n$2, 0):
seq(a(n), n=0..20); # Alois P. Heinz, May 12 2023
CROSSREFS
KEYWORD
nonn
AUTHOR
Seiichi Manyama, May 12 2023
STATUS
approved