Number of ternary trees with n edges and having no vertices of degree 1. A ternary tree is a rooted tree in which each vertex has at most three children and each child of a vertex is designated as its left or middle or right child.
A120984
Number of ternary trees with n edges and having no vertices of degree 1. A ternary tree is a rooted tree in which each vertex has at most three children and each child of a vertex is designated as its left or middle or right child.
Terms
- a(0) =1a(1) =0a(2) =3a(3) =1a(4) =18a(5) =15a(6) =138a(7) =189a(8) =1218a(9) =2280a(10) =11826a(11) =27225a(12) =123013a(13) =325611a(14) =1346631a(15) =3919188a(16) =15318342a(17) =47563620a(18) =179405250a(19) =582336054a(20) =2148831144a(21) =7191954822a(22) =26193070008a(23) =89559039141a(24) =323765075223
External references
- oeis: A120984