Triangle read by rows: T(n,k) is the number of ordered trees with n edges and having k vertices of outdegree 2 that have (two) leaves as their (two) children.
A178519
Triangle read by rows: T(n,k) is the number of ordered trees with n edges and having k vertices of outdegree 2 that have (two) leaves as their (two) children.
Terms
- a(0) =1a(1) =1a(2) =1a(3) =1a(4) =4a(5) =1a(6) =11a(7) =3a(8) =32a(9) =10a(10) =98a(11) =33a(12) =1a(13) =309a(14) =114a(15) =6a(16) =998a(17) =402a(18) =30a(19) =3285a(20) =1439a(21) =137a(22) =1a(23) =10981a(24) =5205a(25) =600a(26) =10a(27) =37178a(28) =18976a(29) =2562
External references
- oeis: A178519