A227807 Number of rooted identity trees with n nodes and exactly 3 subtrees from the root.

1, 2, 5, 12, 28, 65, 152, 351, 818, 1907, 4460, 10453, 24581, 57922, 136860, 324088, 769188, 1829282, 4359048, 10406106, 24885240, 59607192, 142996100, 343540150, 826468374, 1990841497, 4801534221, 11593858684, 28025623617, 67816875039, 164268161404

Offset

7,2

Links

Alois P. Heinz, Table of n, a(n) for n = 7..800

Example

:    o    :      o      o    :
:   /|\   :     /|\    /|\   :
:  o o o  :    o o o  o o o  :
:  | |    :   /| |    | |    :
:  o o    :  o o o    o o    :
:  |      :  |        |      :
:  o      :  o        o      :
:         :           |      :
:  n=7    :  n=8      o      :

Crossrefs

Column k=3 of A227774.

Sequence in context: A129519 A034943 A181984 * A206721 A209173 A297496

Adjacent sequences: A227804 A227805 A227806 * A227808 A227809 A227810

Keyword

nonn

Author

Alois P. Heinz, Jul 31 2013

Status

approved