Number of unlabeled trees on n nodes with maximum degree three and three vertices of degree three.

Terms

a(0) =1a(1) =3a(2) =10a(3) =24a(4) =55a(5) =109a(6) =206a(7) =360a(8) =606a(9) =970a(10) =1508a(11) =2264a(12) =3322a(13) =4750a(14) =6668a(15) =9176a(16) =12439a(17) =16597a(18) =21870a(19) =28448a(20) =36617a(21) =46627a(22) =58842a(23) =73584a(24) =91308a(25) =112420a(26) =137480a(27) =166992a(28) =201636a(29) =242028