A227807 - OEIS

%I #5 Jul 31 2013 17:10:36

%S 1,2,5,12,28,65,152,351,818,1907,4460,10453,24581,57922,136860,324088,

%T 769188,1829282,4359048,10406106,24885240,59607192,142996100,

%U 343540150,826468374,1990841497,4801534221,11593858684,28025623617,67816875039,164268161404

%N Number of rooted identity trees with n nodes and exactly 3 subtrees from the root.

%H Alois P. Heinz, <a href="/A227807/b227807.txt">Table of n, a(n) for n = 7..800</a>

%e :    o    :      o      o    :

%e :   /|\   :     /|\    /|\   :

%e :  o o o  :    o o o  o o o  :

%e :  | |    :   /| |    | |    :

%e :  o o    :  o o o    o o    :

%e :  |      :  |        |      :

%e :  o      :  o        o      :

%e :         :           |      :

%e :  n=7    :  n=8      o      :

%Y Column k=3 of A227774.

%K nonn

%O 7,2

%A _Alois P. Heinz_, Jul 31 2013