Number of graphs with n edges.

Terms

a(0) =1a(1) =1a(2) =2a(3) =5a(4) =11a(5) =26a(6) =68a(7) =177a(8) =497a(9) =1476a(10) =4613a(11) =15216a(12) =52944a(13) =193367a(14) =740226a(15) =2960520a(16) =12334829a(17) =53394755a(18) =239544624a(19) =1111261697a(20) =5320103252a(21) =26237509076a(22) =133087001869a(23) =693339241737