Number of ordered rooted binary trees with n leaves and with minimal Sackin tree balance index.

Terms

a(0) =1a(1) =1a(2) =1a(3) =2a(4) =1a(5) =4a(6) =6a(7) =4a(8) =1a(9) =8a(10) =28a(11) =56a(12) =70a(13) =56a(14) =28a(15) =8a(16) =1a(17) =16a(18) =120a(19) =560a(20) =1820a(21) =4368a(22) =8008a(23) =11440a(24) =12870a(25) =11440a(26) =8008a(27) =4368a(28) =1820a(29) =560