Number of disconnected regular simple graphs on n vertices with girth exactly 6.

Terms

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