%I A054939
%S A054939 1,0,3,16,376,13292,933488,125771776,33148165696,17248244115968,
%T A054939 17820828776291072,36677298103363352704,150636101324832283976704,
%U A054939 1235824405515221864531935232,20263840468865240117348466818048
%N A054939 Number of connected labeled graphs with n nodes and an even number of 
               edges.
%H A054939 V. A. Liskovets, <a href="http://www.cs.uwaterloo.ca/journals/JIS/index.html">
               Some easily derivable sequences</a>, J. Integer Sequences, 3 (2000), 
               #00.2.2.
%F A054939 a(n)=(A001187(n)+(-1)^(n-1)*A000142(n-1))/2.
%Y A054939 Sequence in context: A013923 A053466 A005031 this_sequence A081782 A081780 
               A002794
%Y A054939 Adjacent sequences: A054936 A054937 A054938 this_sequence A054940 A054941 
               A054942
%K A054939 nonn,easy
%O A054939 1,3
%A A054939 N. J. A. Sloane (njas(AT)research.att.com), May 24 2000
%E A054939 More terms from Vladeta Jovovic (vladeta(AT)eunet.rs), Jul 17 2000