%N Graph code numbers of simple graphs in numerical order.
%C Every simple graph has a symmetric adjacency matrix whose lower triangular part by rows represents a little-endian binary number of which the minimum value over all isomorphic graphs gives the graph code number. Adding isolated vertices will not change the graph code number.
%C Study of the patterns and gaps in the sequence appears to be quite interesting.
%C The number of terms that are less than 2^(n*(n-1)/2) is equal to A000088(n). - _Vladimir Kulipanov_, Oct 13 2015
%D F. Harary, Problems involving graphical numbers, in Colloq. Math. Soc. Janos Bolyai, 4 (1970) 625-635. Look at his 'mincode numbers'.
%D K. R. Parthasarathy, Graph Code Numbers, preprint.
%H Vladimir Kulipanov, <a href="/A076184/a076184.txt">Table of n, a(n) for n = 1..156</a>
%e a(5)=11 in binary (with 0's prepended to give a triangular number of digits) is 001011 so adjacency matrix [0,1,1,1; 1,0,0,0; 1,0,0,0; 1,0,0,0].
%e a(6)=12 in binary is 001100 so adjacency matrix [[0,0,0,1; 0,0,1,0; 0,1,0,0; 1,0,0,0].
%Y Cf. A000088.
%A K. R. Parthasarathy (nuns(AT)vsnl.com), Nov 02 2002