%I A003093 M1977
%S A003093 1,2,10,83,690,6412,61842,457025
%N A003093 Number of planar 2-trees with n nodes.
%D A003093 N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, 
               Academic Press, 1995 (includes this sequence).
%D A003093 E. M. Palmer and R. C. Read, on the number of plane 2-trees, J. Lond. 
               Math. Soc., 6 (1973), 583-592.
%H A003093 <a href="Sindx_Tra.html#trees">Index entries for sequences related to 
               trees</a>
%Y A003093 Sequence in context: A112487 A089469 A111265 this_sequence A006679 A050390 
               A101878
%Y A003093 Adjacent sequences: A003090 A003091 A003092 this_sequence A003094 A003095 
               A003096
%K A003093 nonn
%O A003093 3,2
%A A003093 N. J. A. Sloane (njas(AT)research.att.com).