Number of anti-binary (no binary branchings) unlabeled rooted trees with n nodes.

Terms

a(0) =1a(1) =1a(2) =1a(3) =2a(4) =4a(5) =8a(6) =16a(7) =32a(8) =66a(9) =139a(10) =297a(11) =642a(12) =1404a(13) =3097a(14) =6888a(15) =15428a(16) =34770a(17) =78785a(18) =179397a(19) =410264a(20) =941935a(21) =2170275a(22) =5016604a(23) =11630024a(24) =27034824a(25) =63000261a(26) =147148341a(27) =344419767a(28) =807746487a(29) =1897829065