A245152 - OEIS

A245152

Number of n-node unlabeled rooted trees with thickening limbs.

1, 1, 2, 3, 5, 7, 12, 17, 28, 42, 69, 105, 176, 275, 460, 740, 1244, 2030, 3440, 5695, 9688, 16243, 27758, 46948, 80610, 137401, 236796, 406258, 702720, 1211954, 2103536, 3644413, 6344632, 11035287, 19265731, 33621510, 58848963, 103003059, 180712466, 317122290

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OFFSET

1,3

COMMENTS

Also the number of (n+1)-node unlabeled rooted trees with thickening limbs and root outdegree (branching factor) 1.

In a rooted tree with thickening limbs the outdegree of a parent node is smaller than or equal to the outdegree of any of its non-leaf child nodes.

LINKS

Alois P. Heinz, Table of n, a(n) for n = 1..150

FORMULA

a(n) = Sum_{k=0..n-1} A245151(n,k).

CROSSREFS

Row sums of A245151, also (with offset 2) column k=1 of A245151.