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arXiv · 2009.06793

Counting ternary trees according to the number of middle edges and factorizing into $(3/2)$-ary trees

Helmut Prodinger
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Abstract

The sequence A120986 in the Encyclopedia of Integer Sequences counts ternary trees according to the number of nodes and the number of middle edges. Using a certain substition, the underlying cubic equation can be factored. This leads to an extension of the concept of $(3/2)$-ary trees, introduced by Knuth in his christmas lecture from 2014.

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Helmut Prodinger. 2020-09-14. Counting ternary trees according to the number of middle edges and factorizing into $(3/2)$-ary trees. https://arxiv.org/abs/2009.06793

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