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A231281
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Number of n X 4 0..3 arrays x(i,j) with each element horizontally or antidiagonally next to at least one element with value (x(i,j)+1) mod 4, and upper left element zero.
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1
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0, 6, 76, 1170, 18208, 278758, 4294812, 66052162, 1016260448, 15634778470, 240537044748, 3700602618386, 56932811822272, 875896777768582, 13475447374606748, 207316306566902018, 3189508270154101568
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OFFSET
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1,2
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LINKS
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FORMULA
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Empirical: a(n) = 9*a(n-1) + 86*a(n-2) + 190*a(n-3) - 29*a(n-4) + a(n-5).
Empirical g.f.: 2*x^2*(1 - x)*(3 + 14*x - x^2) / (1 - 9*x - 86*x^2 - 190*x^3 + 29*x^4 - x^5). - Colin Barker, Sep 28 2018
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EXAMPLE
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Some solutions for n=3:
..0..1..0..3....0..1..2..0....0..1..0..2....0..1..2..1....0..1..0..2
..2..3..1..2....0..3..1..0....2..3..3..0....0..3..3..0....2..3..3..2
..2..0..3..2....1..2..3..2....1..2..1..0....2..2..1..0....2..0..1..0
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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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