Number of simple unlabeled graphs on 2*n nodes with exactly n connected components that are trees or cycles.

A215979

Number of simple unlabeled graphs on 2*n nodes with exactly n connected components that are trees or cycles.

Terms

    a(0) =1a(1) =1a(2) =3a(3) =6a(4) =13a(5) =26a(6) =56a(7) =115a(8) =247a(9) =533a(10) =1175a(11) =2636a(12) =6040a(13) =14078a(14) =33401a(15) =80524a(16) =196897a(17) =487781a(18) =1222279a(19) =3094507a(20) =7905992a(21) =20364597a(22) =52838720a(23) =138001953a(24) =362565398a(25) =957687474a(26) =2542056376a(27) =6777855755a(28) =18146153182a(29) =48766704695

External references