Number of disconnected 2-regular simple graphs on n vertices with girth at least 5.

Terms

a(0) =0a(1) =0a(2) =0a(3) =0a(4) =0a(5) =0a(6) =0a(7) =0a(8) =0a(9) =0a(10) =1a(11) =1a(12) =2a(13) =2a(14) =3a(15) =4a(16) =5a(17) =6a(18) =8a(19) =9a(20) =12a(21) =14a(22) =17a(23) =20a(24) =25a(25) =29a(26) =35a(27) =41a(28) =49a(29) =57