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A232936
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Number of n X 3 0..2 arrays with no element x(i,j) adjacent to value 2-x(i,j) horizontally, vertically or antidiagonally.
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1
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12, 26, 84, 252, 774, 2360, 7212, 22024, 67272, 205466, 627562, 1916768, 5854418, 17881234, 54614930, 166811210, 509494028, 1556155380, 4752989126, 14517127208, 44339883148, 135427981664, 413639750856, 1263386202642, 3858779756370
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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) = a(n-1) + 5*a(n-2) + 4*a(n-3) - a(n-5) for n>6.
Empirical g.f.: 2*x*(6 + 7*x - x^2 - 5*x^3 - x^4 + x^5) / ((1 + x)*(1 - 2*x - 3*x^2 - x^3 + x^4)). - Colin Barker, Oct 06 2018
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EXAMPLE
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Some solutions for n=5:
..0..0..1....2..2..2....2..1..2....0..0..0....1..2..1....2..2..1....2..2..2
..0..0..0....2..2..2....2..2..1....0..0..0....2..2..2....1..2..2....2..2..1
..0..0..0....1..2..1....2..2..2....0..1..0....2..2..2....2..1..2....1..2..2
..0..0..0....2..2..2....1..2..2....0..0..1....2..2..2....2..2..1....2..2..2
..0..1..0....1..2..2....2..1..2....0..0..0....1..2..2....2..2..2....2..2..2
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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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