A227808 Number of rooted identity trees with n nodes and exactly 4 subtrees from the root.

2, 4, 13, 34, 91, 225, 571, 1403, 3466, 8468, 20703, 50389, 122673, 298090, 724433, 1759595, 4274819, 10385533, 25240007, 61358410, 149226407, 363077813, 883818374, 2152462147, 5244790003, 12786162151, 31187100089, 76108058977, 185825963102, 453940832229

Offset

11,1

Links

Alois P. Heinz, Table of n, a(n) for n = 11..800

Example

:        o            o      :
:      /( )\        /( )\    :
:     / | | \      / | | \   :
:    o  o o  o    o  o o  o  :
:   /|  | |       |  | |     :
:  o o  o o       o  o o     :
:  |    |         |  |       :
:  o    o         o  o       :
:                 |          :
:  n=11           o          :

Crossrefs

Column k=4 of A227774.

Sequence in context: A148228 A148229 A148230 * A148231 A148232 A148233

Adjacent sequences: A227805 A227806 A227807 * A227809 A227810 A227811

Keyword

nonn

Author

Alois P. Heinz, Jul 31 2013

Status

approved