Hi and welcome to the Matladpi blog! In this post I will concentrate on the enumeration of homeomorphically irreducible trees, calculating the quantity of these for size v = 21. Here is a picture:

So, first we evaluated the number of forms for branches of sizes 1 - 10 with the branch form generator (BFG). The size 11 case will be used in some later posts.

Next, we will enumerate h21 by using the algorithm BFG -> TGA, where TGA stands for tree generation algorithm.

Here are the pictures:

So h21 = 5671. Njäf! said.

I am Jesse Sakari Hyttinen and I will see you in the next post!