A246566 Number of rooted ordered trees with n non-root nodes such that the branch lengths are weakly decreasing.
1, 1, 2, 4, 10, 24, 62, 155, 396, 992, 2504, 6228, 15512, 38220, 94059, 229498, 558642, 1350384, 3255138, 7801327, 18642118, 44329833, 105111283, 248184255, 584396849, 1371048495, 3208318247, 7483522231, 17413665881, 40405120865, 93543352492
Offset: 0
Keywords
Examples
The a(3) = 4 such trees are: : : 1: : [ 1 1 1 ] : [ 0 0 0 ] : : O--o : .--o : .--o : : : 2: : [ 2 1 ] : [ 0 0 ] : : O--o--o : .--o : : : 3: : [ 2 1 ] : [ 0 1 ] : : O--o--o : .--o : : : 4: : [ 3 ] : [ 0 ] : : O--o--o--o : See the Arndt link for all trees for 0 <= n <= 5.
Links
- Joerg Arndt, All trees for 0 <= n <= 5