login
A292232
Number of (unlabeled) rooted trees with n leaf nodes and without unary nodes such that the maximum of the node outdegrees equals six.
2
1, 2, 7, 23, 78, 261, 887, 3008, 10268, 35112, 120445, 413979, 1425919, 4919635, 17000553, 58828575, 203826882, 707008418, 2454916048, 8532126320, 29679297122, 103322632386, 359962092302, 1254914172463, 4377704183644, 15280415561913, 53365850603107
OFFSET
6,2
MAPLE
b:= proc(n, i, v, k) option remember; `if`(n=0,
`if`(v=0, 1, 0), `if`(i<1 or v<1 or n<v, 0,
`if`(v=n, 1, add(binomial(A(i, k)+j-1, j)*
b(n-i*j, i-1, v-j, k), j=0..min(n/i, v)))))
end:
A:= proc(n, k) option remember; `if`(n<2, n,
add(b(n, n+1-j, j, k), j=2..min(n, k)))
end:
a:= n-> A(n, 6)-A(n, 5):
seq(a(n), n=6..35);
CROSSREFS
Column k=6 of A292086.
Sequence in context: A067324 A047062 A292231 * A292233 A292234 A292235
KEYWORD
nonn
AUTHOR
Alois P. Heinz, Sep 12 2017
STATUS
approved