OFFSET
8,2
COMMENTS
A triad is an orientation of a tree that has a single vertex of degree 3 and otherwise only vertices of degree 2 and 1. A triad T is called a core triad if every endomorphism of T is an automorphism.
EXAMPLE
For n = 9 the a(9) = 3 solutions are:
1. 0111,000,1
2. 01000,00,1
3. 01111,00,1
Here 0 stands for forward edge, 1 stands for backward edge, and the three words stand for the three paths that leave the vertex of degree 3 of the triad.
CROSSREFS
KEYWORD
nonn,more
AUTHOR
Michael Wernthaler, Mar 21 2021
STATUS
approved