%I A006387 M4237
%S A006387 1,6,40,320,2946
%N A006387 Genus 1 maps with n edges.
%D A006387 N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, 
               Academic Press, 1995 (includes this sequence).
%D A006387 Walsh, T. R. S.; Generating nonisomorphic maps without storing them. 
               SIAM J. Algebraic Discrete Methods 4 (1983), no. 2, 161-178.
%Y A006387 Sequence in context: A081337 A138240 A083805 this_sequence A014481 A000683 
               A143342
%Y A006387 Adjacent sequences: A006384 A006385 A006386 this_sequence A006388 A006389 
               A006390
%K A006387 nonn
%O A006387 2,2
%A A006387 N. J. A. Sloane (njas(AT)research.att.com).