OFFSET
0,9
LINKS
Alois P. Heinz, Table of n, a(n) for n = 0..200
EXAMPLE
a(7) = 1: 1234567.
a(8) = 7: 12345687, 12345786, 12346785, 12356784, 12456783, 13456782, 23456781.
a(9) = 28: 123456987, 123457986, ..., 245678931, 345678921.
MAPLE
b:= proc(u, o, t) option remember; `if`(u+o=0, 1, add(`if`(t=6,
b(o-j, u+j-1, 1), b(u+j-1, o-j, t+1)), j=1..o))
end:
a:= n-> b(0, n, 0):
seq(a(n), n=0..35);
CROSSREFS
KEYWORD
nonn,eigen
AUTHOR
Alois P. Heinz, Oct 02 2013
STATUS
approved