

A339525


Number of unordered pairs of rooted trees with a total of n nodes and an odd total of leaves.


2



0, 0, 0, 1, 3, 8, 19, 47, 119, 309, 805, 2115, 5594, 14920, 40037, 108068, 293124, 798739, 2185380, 6001797, 16538728, 45716315, 126727586, 352214041, 981269274, 2739925455, 7666335708, 21491822234, 60358497108, 169798015580, 478420350367
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OFFSET

1,5


COMMENTS

Equivalently, the number of rooted trees on n+1 nodes, where the root has degree 2, and the number of leaves is odd.
To get a pair of trees with an odd number of leaves one tree must have an even number of leaves and the other an odd number of leaves.


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CROSSREFS



KEYWORD

nonn


AUTHOR



STATUS

approved



