%I #8 Jun 11 2021 13:42:16
%S 1,1,3,19,207,3571,93243,3603139,203658087,16725737971,1985745828483,
%T 339119822487139,82867477502576847,28816562818537878931,
%U 14182270437347915240523,9825699599254424454332419
%N Number of labeled triangle-free connected simple graphs on n vertices.
%C LOG transform of A213434.
%C Labeled version of A024607.
%Y Cf. A024607, A213434.
%K nonn,hard
%O 1,3
%A _Brendan McKay_, Jun 11 2021