%I #6 May 30 2017 22:53:18
%S 1,2,4,9,21,56,158,493,1658
%N Number of not-necessarily connected simple chordless graphs on n vertices.
%H Eric Weisstein's World of Mathematics, <a href="http://mathworld.wolfram.com/ChordlessGraph.html">Chordless Graph</a>
%e 1 node: K_1 (1 graph)
%e 2 nodes: \bar K_2, P_2 = K_2 (2 graphs)
%e 3 nodes: \bar K_3, K_1\cup K_2, P_3, C_3 = K_3 (4 graphs)
%e Here, \bar denotes graph complementation and \cup graph unioning.
%K nonn,more
%O 1,2
%A _Eric W. Weisstein_, May 30 2017