Number of unlabeled series-reduced 2-connected graphs with n edges.

Terms

a(0) =1a(1) =0a(2) =1a(3) =3a(4) =5a(5) =9a(6) =26a(7) =65a(8) =193a(9) =632a(10) =2173a(11) =8049a(12) =31690a(13) =130773a(14) =563849a(15) =2525348a(16) =11702264a(17) =55948154a(18) =275331956a(19) =1392136462a(20) =7221272289a(21) =38380011748a(22) =208778309856