%I M0786
%S 1,2,3,6,11,21,40,77,149,289,563,1099,2152,4222,8299,16339,32217,
%T 63612,125753,248870,493015,977576,1940042,3853117,7658211,15231219,
%U 30312012,60360046,120260317
%N Number of directed site animals on hexagonal lattice.
%C The hexagonal lattice is the familiar 2dimensional lattice in which each point has 6 neighbors. This is sometimes called the triangular lattice.
%D D. Dhar et al., Enumeration of directed site animals on twodimensional lattices, J. Phys. A 15 (1982), L279L284.
%D N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).
%H G. Nebe and N. J. A. Sloane, <a href="http://www.math.rwthaachen.de/~Gabriele.Nebe/LATTICES/A2.html">Home page for hexagonal (or triangular) lattice A2</a>
%K nonn
%O 1,2
%A _Simon Plouffe_ and _N. J. A. Sloane_.
