%I A007171 M1296
%S A007171 1,2,4,16,89,579,3989,28630,210847,1584308
%N A007171 Q-graphs with 2n edges.
%D A007171 R. C. Read, On the enumeration of a class of plane multigraphs, Aequat. 
               Math., 31 (1986), 47-63.
%D A007171 N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, 
               Academic Press, 1995 (includes this sequence).
%Y A007171 Sequence in context: A000831 A000090 A013115 this_sequence A058136 A156335 
               A026089
%Y A007171 Adjacent sequences: A007168 A007169 A007170 this_sequence A007172 A007173 
               A007174
%K A007171 nonn,more
%O A007171 1,2
%A A007171 N. J. A. Sloane (njas(AT)research.att.com).