%I #7 Jan 08 2018 18:35:08
%S 0,0,0,1,7,41,260,1930,17463,200008,3026192,62212319,1742874972,
%T 65794989216,3314857545154,222226981778153,19858056830333695,
%U 2371636836808937036,378993965527624639893
%N Number of chordless cycles in the n-triangular grid graph.
%H Eric Weisstein's World of Mathematics, <a href="http://mathworld.wolfram.com/ChordlessCycle.html">Chordless Cycle</a>
%H Eric Weisstein's World of Mathematics, <a href="http://mathworld.wolfram.com/TriangularGridGraph.html">Triangular Grid Graph</a>
%Y Cf. A112676, A266513.
%K nonn,more
%O 0,5
%A _Eric W. Weisstein_, Jan 02 2018
%E a(7)-a(18) from _Andrew Howroyd_, Jan 08 2018