Number of rooted trees with n nodes, where cycles are allowed instead of subtrees.

Terms

a(0) =0a(1) =1a(2) =1a(3) =3a(4) =6a(5) =13a(6) =29a(7) =71a(8) =176a(9) =454a(10) =1188a(11) =3168a(12) =8542a(13) =23319a(14) =64201a(15) =178249a(16) =498241a(17) =1401344a(18) =3962353a(19) =11257882a(20) =32122442a(21) =92011118a(22) =264474749a(23) =762620137a(24) =2205415254a(25) =6394813039a(26) =18587795338a(27) =54151405093a(28) =158088694125a(29) =462420145673