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%I #5 Apr 23 2021 13:51:49
%S 1,7,19,37,133,535,2615,17641,119940,924944,8924108,102805254,
%T 1407633936,22958195053,437437783099
%N Number of ways to place zero or more nonadjacent 1,1 2,1 3,0 3,1 3,2 4,1 5,1 polyhexes in any orientation on a planar n X n X n triangular grid.
%e Maximal 10 X 10 X 10 example
%e ............0
%e ...........0.1
%e ..........0.1.0
%e .........1.1.1.0
%e ........0.1.0.0.0
%e .......0.1.0.0.1.0
%e ......0.0.0.0.0.1.0
%e .....0.1.0.0.0.1.1.1
%e ....1.1.1.1.1.0.0.1.0
%e ...0.0.0.1.0.0.0.0.1.0
%K nonn
%O 5,2
%A _R. H. Hardin_ Jan 22 2009