cp's OEIS Frontend

A318851 Number of rooted trees with n nodes such that no more than four isomorphic subtrees extend from the same node.

%I A318851 #5 Sep 04 2018 17:14:55
%S A318851 0,1,1,2,4,9,19,46,110,273,684,1746,4503,11758,30943,82118,219341,
%T A318851 589485,1592447,4322433,11781565,32235688,88503331,243750729,
%U A318851 673246211,1864422803,5175655984,14399854855,40146793094,112145140408,313826549732,879685174894
%N A318851 Number of rooted trees with n nodes such that no more than four isomorphic subtrees extend from the same node.
%H A318851 Alois P. Heinz, <a href="/A318851/b318851.txt">Table of n, a(n) for n = 0..2143</a>
%p A318851 h:= proc(n, m, t) option remember; `if`(m=0, binomial(n+t, t),
%p A318851       `if`(n=0, 0, add(h(n-1, m-j, t+1), j=1..min(4, m))))
%p A318851     end:
%p A318851 b:= proc(n, i) option remember; `if`(n=0, 1, `if`(i<1, 0,
%p A318851       add(b(n-i*j, i-1)*h(a(i), j, 0), j=0..n/i)))
%p A318851     end:
%p A318851 a:= n-> `if`(n<2, n, b(n-1$2)):
%p A318851 seq(a(n), n=0..35);
%Y A318851 Column k=4 of A318757.
%K A318851 nonn
%O A318851 0,4
%A A318851 _Alois P. Heinz_, Sep 04 2018