Number of asymmetric (identity) trees with n nodes and 4 leaves.

Terms

a(0) =1a(1) =3a(2) =8a(3) =14a(4) =25a(5) =40a(6) =62a(7) =89a(8) =127a(9) =173a(10) =233a(11) =304a(12) =393a(13) =497a(14) =624a(15) =769a(16) =942a(17) =1139a(18) =1369a(19) =1627a(20) =1925a(21) =2257a(22) =2635a(23) =3053a(24) =3524a(25) =4042a(26) =4621a(27) =5253a(28) =5954a(29) =6717