a(n) is the number of unlabeled graphs on n nodes whose components are unicyclic graphs.

Terms

a(0) =1a(1) =0a(2) =0a(3) =1a(4) =2a(5) =5a(6) =14a(7) =35a(8) =97a(9) =264a(10) =733a(11) =2034a(12) =5728a(13) =16101a(14) =45595a(15) =129327a(16) =368093a(17) =1049520a(18) =2999415a(19) =8584857a(20) =24612114a(21) =70652441a(22) =203075740a(23) =584339171a(24) =1683151508a(25) =4852736072a(26) =14003298194a(27) =40441136815a(28) =116880901512a(29) =338040071375