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A245152 Number of n-node unlabeled rooted trees with thickening limbs. 2
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 (list; graph; refs; listen; history; text; internal format)
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.

Sequence in context: A318185 A048816 A080528 * A334271 A206788 A002965

Adjacent sequences:  A245149 A245150 A245151 * A245153 A245154 A245155

KEYWORD

nonn

AUTHOR

Alois P. Heinz, Jul 12 2014

STATUS

approved

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Last modified April 14 07:59 EDT 2021. Contains 342946 sequences. (Running on oeis4.)