Number of rooted identity trees with n nodes and exactly 4 subtrees from the root.

Terms

a(0) =2a(1) =4a(2) =13a(3) =34a(4) =91a(5) =225a(6) =571a(7) =1403a(8) =3466a(9) =8468a(10) =20703a(11) =50389a(12) =122673a(13) =298090a(14) =724433a(15) =1759595a(16) =4274819a(17) =10385533a(18) =25240007a(19) =61358410a(20) =149226407a(21) =363077813a(22) =883818374a(23) =2152462147a(24) =5244790003a(25) =12786162151a(26) =31187100089a(27) =76108058977a(28) =185825963102a(29) =453940832229