Number of trees in an n-node wheel.

Terms

a(0) =1a(1) =1a(2) =1a(3) =2a(4) =3a(5) =6a(6) =11a(7) =20a(8) =36a(9) =64a(10) =108a(11) =179a(12) =292a(13) =464a(14) =727a(15) =1124a(16) =1714a(17) =2585a(18) =3866a(19) =5724a(20) =8418a(21) =12290a(22) =17830a(23) =25713a(24) =36898a(25) =52664a(26) =74837a(27) =105873a(28) =149178a(29) =209364