Number of ternary rooted identity (distinct subtrees) trees with n nodes.

Terms

a(0) =1a(1) =1a(2) =1a(3) =2a(4) =3a(5) =6a(6) =12a(7) =25a(8) =52a(9) =113a(10) =245a(11) =542a(12) =1205a(13) =2707a(14) =6113a(15) =13907a(16) =31780a(17) =73010a(18) =168399a(19) =389991a(20) =906231a(21) =2112742a(22) =4939689a(23) =11580640a(24) =27216387a(25) =64110091a(26) =151334814a(27) =357938832a(28) =848153045a(29) =2013190671