Number of trees on [n], rooted at 1, in which 2 is a descendant of 3.
A129137
Number of trees on [n], rooted at 1, in which 2 is a descendant of 3.
Terms
- a(0) =0a(1) =0a(2) =1a(3) =5a(4) =37a(5) =366a(6) =4553a(7) =68408a(8) =1206405a(9) =24447440a(10) =560041201a(11) =14315792256a(12) =404057805989
External references
- oeis: A129137