OFFSET
0,3
LINKS
Alois P. Heinz, Table of n, a(n) for n = 0..150
MAPLE
with(combinat):
b:= proc(n, i) option remember; unapply(`if`(n=0 or i=1, x^n,
expand(add((i-1)!^j*multinomial(n, n-i*j, i$j)/j!*
x^(igcd(i, 9)*j)*b(n-i*j, i-1)(x), j=0..n/i))), x)
end:
a:= n-> add(binomial(n-1, j-1)*n^(n-j)*b(j$2)(n), j=0..n):
seq(a(n), n=0..20);
CROSSREFS
KEYWORD
nonn
AUTHOR
Alois P. Heinz, Aug 06 2014
STATUS
approved