A244536 - OEIS

%I #8 Jul 02 2014 11:42:16

%S 1,0,0,0,0,0,0,7,15,16,17,18,19,20,91,253,529,852,1225,1651,2133,3493,

%T 6931,14095,27156,47648,77297,118031,182462,300441,527398,954712,

%U 1722370,3015910,5074611,8342271,13730760,23036563,39558564,68974240,120541276

%N Number of ordered unlabeled rooted trees with n nodes such that the minimal outdegree of inner nodes equals 7.

%H Alois P. Heinz, <a href="/A244536/b244536.txt">Table of n, a(n) for n = 8..1000</a>

%p b:= proc(n, t, k) option remember; `if`(n=0,

%p       `if`(t in [0, k], 1, 0), `if`(t>n, 0, add(b(j-1, k$2)*

%p        b(n-j, max(0, t-1), k), j=1..n)))

%p     end:

%p a:= n-> b(n-1, 7$2) -b(n-1, 8$2):

%p seq(a(n), n=8..50);

%Y Column k=7 of A244530.

%Y Cf. A244461.

%K nonn

%O 8,8

%A _Joerg Arndt_ and _Alois P. Heinz_, Jun 29 2014