Number of unlabeled minimally 2-connected graphs with n nodes (also called "blocks").

Terms

a(0) =1a(1) =1a(2) =2a(3) =3a(4) =6a(5) =12a(6) =28a(7) =68a(8) =184a(9) =526a(10) =1602a(11) =5075a(12) =16711a(13) =56428a(14) =195003a(15) =685649a(16) =2447882a(17) =8850157a(18) =32359428a(19) =119492766a(20) =445236635a(21) =1672636369a(22) =6331624545a(23) =24138404479a(24) =92640942148a(25) =357805122286