Number of unlabeled rooted semi-identity trees with n nodes.

Terms

a(0) =0a(1) =1a(2) =1a(3) =2a(4) =4a(5) =8a(6) =18a(7) =41a(8) =98a(9) =237a(10) =591a(11) =1488a(12) =3805a(13) =9820a(14) =25593a(15) =67184a(16) =177604a(17) =472177a(18) =1261998a(19) =3388434a(20) =9136019a(21) =24724904a(22) =67141940a(23) =182892368a(24) =499608724a(25) =1368340326a(26) =3756651116a(27) =10336434585a(28) =28499309291a(29) =78727891420