Number of unlabeled simple graphs covering n vertices with at most n edges.

Terms

a(0) =1a(1) =0a(2) =1a(3) =2a(4) =5a(5) =10a(6) =28a(7) =68a(8) =193a(9) =534a(10) =1568a(11) =4635a(12) =14146a(13) =43610a(14) =137015a(15) =435227a(16) =1400058a(17) =4547768a(18) =14917504a(19) =49348612a(20) =164596939a(21) =553177992a(22) =1872805144a(23) =6385039022a(24) =21917878860a(25) =75739158828a(26) =263438869515a(27) =922219844982