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

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.

No reviews yet.

No comments yet.