The number of unlabeled graphs on n nodes with degree of 1 or 2.

Terms

a(0) =1a(1) =0a(2) =1a(3) =2a(4) =3a(5) =4a(6) =8a(7) =10a(8) =17a(9) =24a(10) =36a(11) =50a(12) =76a(13) =102a(14) =148a(15) =204a(16) =285a(17) =386a(18) =537a(19) =718a(20) =980a(21) =1308a(22) =1756a(23) =2324a(24) =3097a(25) =4060a(26) =5353a(27) =6986a(28) =9124a(29) =11822