%I A054923
%S A054923 1,0,1,0,0,1,0,0,1,2,0,0,0,2,3,0,0,0,1,5,6,0,0,0,1,5,13,11,0,0,0,0,4,19,
               33,23,0,0,0,0,
%T A054923 2,22,67,89,47,0,0,0,0,1,20,107,236,240,106,0,0,0,0,1,14,132,486,797,
%U A054923 657,235,0,0,0,0,0,9,138,814,2075,2678,1806,551,0,0,0,0,0,2,95,1454,8404,
               22950,33851,28908
%N A054923 Triangle read by rows: number of connected graphs with k >= 0 edges and 
               n nodes (1<=n<=k+1).
%C A054923 The diagonal n = k+1 is A000055(n). [From Jonathan Vos Post (jvospost3(AT)gmail.com), 
               Aug 10 2008]
%D A054923 G. A. Baker et al., High-temperature expansions for the spin-1/2 Heisenberg 
               model, Phys. Rev., 164 (1967), 800-817.
%D A054923 F. Harary and E. M. Palmer, Graphical Enumeration, Academic Press, NY, 
               1973, p. 93, Table 4.2.2; p. 241, Table A2.
%H A054923 Gordon Royle, <a href="http://www.cs.uwa.edu.au/~gordon/remote/graphs/
               index.html#nums">Small graphs</a>
%e A054923 1; 0 1; 0 0 1; 0 0 1 2; 0 0 0 2 3; 0 0 0 1 5 6; ... (so with 5 edges 
               there's 1 graph with 4 nodes, 5 with 5 nodes and 6 with 6 nodes). 
               [Typo corrected by Anders Haglund, Jul 08 2008]
%Y A054923 Cf. A002905, A008406, A046751, A054924, A046742.
%Y A054923 Sequence in context: A108921 A071548 A143063 this_sequence A057108 A063958 
               A126164
%Y A054923 Adjacent sequences: A054920 A054921 A054922 this_sequence A054924 A054925 
               A054926
%K A054923 nonn,easy,nice,tabl
%O A054923 0,10
%A A054923 N. J. A. Sloane (njas(AT)research.att.com).