Number of ordered rooted trees with n nodes, most of which are leaves.

Terms

a(0) =1a(1) =0a(2) =1a(3) =1a(4) =7a(5) =11a(6) =66a(7) =127a(8) =715a(9) =1549a(10) =8398a(11) =19691a(12) =104006a(13) =258194a(14) =1337220a(15) =3467115a(16) =17678835a(17) =47440745a(18) =238819350a(19) =659060677a(20) =3282060210a(21) =9271024542a(22) =45741281820a(23) =131788178171a(24) =644952073662