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A268094
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Number of 2 X n 0..2 arrays with every repeated value in every row not one larger and in every column one larger mod 3 than the previous repeated value, and upper left element zero.
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1
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3, 27, 243, 2028, 16428, 129792, 1009200, 7756992, 59140800, 448278528, 3383655168, 25462705152, 191189978112, 1433272320000, 10732091092992, 80291457712128, 600321157939200, 4486422252748800, 33517530883227648
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OFFSET
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1,1
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LINKS
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FORMULA
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Empirical: a(n) = 14*a(n-1) - 44*a(n-2) - 88*a(n-3) + 352*a(n-4) + 320*a(n-5) - 256*a(n-6).
Empirical g.f.: 3*x*(1 - 5*x - x^2 + 26*x^3 + 16*x^4 - 16*x^5) / ((1 + 2*x)*(1 - 4*x)*(1 - 8*x + 4*x^2)*(1 - 4*x - 8*x^2)). - Colin Barker, Jan 11 2019
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EXAMPLE
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Some solutions for n=4:
..0..2..0..1....0..0..2..2....0..2..1..2....0..1..1..2....0..2..1..0
..2..0..1..1....2..1..0..1....0..2..1..0....0..0..0..0....2..0..1..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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