Number of rooted forests with n nodes in which each component contains at least two nodes.

Terms

a(0) =1a(1) =0a(2) =1a(3) =2a(4) =5a(5) =11a(6) =28a(7) =67a(8) =171a(9) =433a(10) =1123a(11) =2924a(12) =7720a(13) =20487a(14) =54838a(15) =147570a(16) =399466a(17) =1086312a(18) =2967517a(19) =8137552a(20) =22395604a(21) =61833349a(22) =171227674a(23) =475442129a(24) =1323449661a(25) =3692461865a(26) =10324097819a(27) =28923331940a(28) =81179488039a(29) =228240293289