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%I #16 Jan 03 2019 03:11:16
%S 1,6,18,54,162,474,1398,4074,11898,34554,100302,290322,839382,2422626,
%T 6984342,20110806,57851358,166258242,477419658,1369878582,3927963138,
%U 11255743434,32235116502,92267490414,263968559874,754837708494,2157584748150,6164626128066,17606866229010
%N Number of n-step walks on hexagonal lattice (no points repeated, no adjacent points unless consecutive in path).
%C The hexagonal lattice is the familiar 2-dimensional lattice in which each point has 6 neighbors. This is sometimes called the triangular lattice.
%C Fisher and Hiley give 290334 and 839466 as their last terms instead of 290322 and 839382 (see A002933). Douglas McNeil confirms the correction on the seqfan list Nov 27 2010.
%D N. J. A. Sloane, A Handbook of Integer Sequences, Academic Press, 1973 (includes this sequence).
%D N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).
%H M. E. Fisher and B. J. Hiley, <a href="http://dx.doi.org/10.1063/1.1731729">Configuration and free energy of a polymer molecule with solvent interaction</a>, J. Chem. Phys., 34 (1961), 1253-1267.
%H G. Nebe and N. J. A. Sloane, <a href="http://www.math.rwth-aachen.de/~Gabriele.Nebe/LATTICES/A2.html">Home page for hexagonal (or triangular) lattice A2</a>
%Y Cf. A173380 for square lattice equivalent.
%K nonn,walk
%O 0,2
%A _Joseph Myers_, Nov 27 2010
%E a(19)-a(28) from _Bert Dobbelaere_, Jan 02 2019
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