Number of asymmetric trees with n nodes (also called identity trees).

Terms

a(0) =1a(1) =0a(2) =0a(3) =0a(4) =0a(5) =0a(6) =1a(7) =1a(8) =3a(9) =6a(10) =15a(11) =29a(12) =67a(13) =139a(14) =310a(15) =667a(16) =1480a(17) =3244a(18) =7241a(19) =16104a(20) =36192a(21) =81435a(22) =184452a(23) =418870a(24) =955860a(25) =2187664a(26) =5025990a(27) =11580130a(28) =26765230a(29) =62027433