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%I #3 Mar 31 2012 12:35:35
%S 1,5,2,4,25,64,249,2376,9030,76249,1598732,10091912,165533393,
%T 6511049130,90909213960,2908246084285,219536965840260,5801006454694383
%N Number of nXnXn triangular nonnegative integer arrays, symmetric under 120 degree rotation, with all sums of an element and its neighbors <= 4
%e Some solutions for n=4
%e .....0........1........1........1........1........2........2........3...
%e ....0.0......0.0......0.0......0.1......0.0......1.0......0.0......0.0..
%e ...0.3.0....0.2.0....0.3.0....1.1.0....0.0.0....0.0.1....0.0.0....0.1.0.
%e ..0.0.0.0..1.0.0.1..1.0.0.1..1.0.1.1..1.0.0.1..2.1.0.2..2.0.0.2..3.0.0.3
%e ------
%e .....1........0........4........1........1........2........2........0...
%e ....1.0......0.0......0.0......1.0......0.1......0.1......0.0......0.1..
%e ...0.1.1....0.1.0....0.0.0....0.0.1....1.0.0....1.0.0....0.1.0....1.0.0.
%e ..1.1.0.1..0.0.0.0..4.0.0.4..1.1.0.1..1.0.1.1..2.0.1.2..2.0.0.2..0.0.1.0
%K nonn
%O 0,2
%A _R. H. Hardin_ Oct 09 2009
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