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A270607
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Number of 2 X 2 X 2 triangular 0..n arrays with some element plus some adjacent element totaling n+1 or n-1 exactly once.
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1
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6, 0, 36, 36, 96, 120, 204, 252, 360, 432, 564, 660, 816, 936, 1116, 1260, 1464, 1632, 1860, 2052, 2304, 2520, 2796, 3036, 3336, 3600, 3924, 4212, 4560, 4872, 5244, 5580, 5976, 6336, 6756, 7140, 7584, 7992, 8460, 8892, 9384, 9840, 10356, 10836, 11376
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OFFSET
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1,1
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COMMENTS
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LINKS
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FORMULA
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Empirical: a(n) = 2*a(n-1) -2*a(n-3) +a(n-4) for n>5.
Empirical for n mod 2 = 0: a(n) = 6*n^2 - 18*n + 12 for n>1.
Empirical for n mod 2 = 1: a(n) = 6*n^2 - 18*n + 36 for n>1.
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EXAMPLE
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Some solutions for n=4
...4....2....4....4....3....2....1....0....1....3....1....4....0....1....0....2
..0.3..4.3..1.0..2.3..2.4..3.4..4.3..4.3..0.3..4.0..3.0..3.2..2.1..4.0..1.2..0.1
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CROSSREFS
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KEYWORD
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nonn
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AUTHOR
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STATUS
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approved
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