Total number of fixed points in trees with n nodes.

Terms

a(0) =1a(1) =0a(2) =1a(3) =1a(4) =5a(5) =10a(6) =31a(7) =72a(8) =201a(9) =509a(10) =1374a(11) =3587a(12) =9647a(13) =25686a(14) =69348a(15) =187052a(16) =508480a(17) =1384959a(18) =3791466a(19) =10407842a(20) =28677319a(21) =79231664a(22) =219557624a(23) =609922977a(24) =1698526750a(25) =4740469708a(26) =13258136509a(27) =37151664771a(28) =104294992317a(29) =293279485007