%I #12 May 04 2018 04:48:21

%S 0,2,6,28,148,1144,13128,250240,8295664,494367376,53628829952,

%T 10655018252544,3893626388008448,2627758027841688960,

%U 3289042848785452985600,7666804477507744021487616,33416397343695235205887366144,273365202164844511328577434284160

%N Birooted graphs: number of unlabeled graphs with n nodes rooted at 2 indistinguishable roots.

%F a(n) = 2 * A126122(n). - _Alois P. Heinz_, May 01 2018

%Y Cf. A303831 (connected), A303833 (trees), A126122.

%K nonn

%O 1,2

%A _Brendan McKay_, May 01 2018