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Number of nXnXn triangular 1..3 arrays with all 1s connected, all 2s connected, all 3s connected, 1 at the top vertex, 2 at the lower left, and 3 at the lower right, and no value having more than 5 identical values adjacent
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%I #3 Mar 31 2012 12:35:35

%S 1,17,171,1928,29840,718188,28564256

%N Number of nXnXn triangular 1..3 arrays with all 1s connected, all 2s connected, all 3s connected, 1 at the top vertex, 2 at the lower left, and 3 at the lower right, and no value having more than 5 identical values adjacent

%e Some solutions for n=4

%e ......1..........1..........1..........1..........1..........1..........1....

%e .....2.2........1.3........3.3........1.1........2.1........3.1........3.1...

%e ....2.3.2......1.1.3......2.2.3......1.3.3......2.2.3......3.3.3......3.1.3..

%e ...2.3.3.3....2.1.3.3....2.3.3.3....2.2.3.3....2.2.3.3....2.3.3.3....2.3.3.3.

%e ------

%e ......1..........1..........1..........1..........1..........1..........1....

%e .....2.1........1.1........1.1........1.1........1.1........3.3........1.1...

%e ....2.2.1......1.1.1......3.3.1......1.2.3......3.3.3......3.3.3......1.1.3..

%e ...2.1.1.3....2.3.3.3....2.3.3.3....2.2.3.3....2.2.2.3....2.2.3.3....2.1.3.3.

%K nonn

%O 2,2

%A _R. H. Hardin_ Aug 24 2009