OFFSET
9,3
LINKS
Alois P. Heinz, Table of n, a(n) for n = 9..579
Wikipedia, Partition of a set
MAPLE
b:= proc(n, k, m, l) option remember; `if`(n<1, 1,
`if`(l-n>k, 0, b(n-1, k, m+1, n))+m*b(n-1, k, m, l))
end:
A:= (n, k)-> b(n-1, min(k, n-1), 1, n):
a:= n-> (k-> A(n, k)-A(n, k-1))(9):
seq(a(n), n=9..30);
CROSSREFS
KEYWORD
nonn
AUTHOR
Alois P. Heinz, Dec 29 2018
STATUS
approved