Number of n-node unlabeled forests that have 2 non-isomorphic components.

Terms

a(0) =0a(1) =1a(2) =1a(3) =2a(4) =3a(5) =6a(6) =11a(7) =22a(8) =44a(9) =93a(10) =202a(11) =451a(12) =1033a(13) =2422a(14) =5792a(15) =14075a(16) =34734a(17) =86761a(18) =219188a(19) =558984a(20) =1437927a(21) =3726535a(22) =9723678a(23) =25525112a(24) =67374649a(25) =178723358a(26) =476263051a(27) =1274448596a(28) =3423491458a(29) =9229075121