%I A006407 M1157
%S A006407 1,1,2,4,8,20,58,177
%N A006407 Number of 2-connected planar maps.
%D A006407 N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, 
               Academic Press, 1995 (includes this sequence).
%D A006407 Walsh, T. R. S.; Generating nonisomorphic maps without storing them. 
               SIAM J. Algebraic Discrete Methods 4 (1983), no. 2, 161-178.
%Y A006407 Sequence in context: A082279 A113180 A000116 this_sequence A100447 A112278 
               A059731
%Y A006407 Adjacent sequences: A006404 A006405 A006406 this_sequence A006408 A006409 
               A006410
%K A006407 nonn
%O A006407 3,3
%A A006407 N. J. A. Sloane (njas(AT)research.att.com).