Number of simple unlabeled graphs on n nodes with exactly 1 connected component that is a tree or a cycle.

A215981

Number of simple unlabeled graphs on n nodes with exactly 1 connected component that is a tree or a cycle.

Terms

    a(0) =1a(1) =1a(2) =2a(3) =3a(4) =4a(5) =7a(6) =12a(7) =24a(8) =48a(9) =107a(10) =236a(11) =552a(12) =1302a(13) =3160a(14) =7742a(15) =19321a(16) =48630a(17) =123868a(18) =317956a(19) =823066a(20) =2144506a(21) =5623757a(22) =14828075a(23) =39299898a(24) =104636891a(25) =279793451a(26) =751065461a(27) =2023443033a(28) =5469566586a(29) =14830871803

External references