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A232150
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Number of 2 X n 0..2 arrays with every 0 next to a 1 and every 1 next to a 2 horizontally, diagonally or antidiagonally.
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1
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1, 23, 191, 1299, 9097, 65837, 474721, 3410799, 24510495, 176212555, 1266835473, 9107139805, 65470085209, 470658881191, 3383528394527, 24323895055139, 174862377541881, 1257070592095501, 9036972483506993, 64966018290364927
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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) = 6*a(n-1) + 4*a(n-2) + 25*a(n-3) + 60*a(n-4) - 24*a(n-5) - 72*a(n-6).
Empirical g.f.: x*(1 + 17*x + 49*x^2 + 36*x^3 - 96*x^4 - 72*x^5) / (1 - 6*x - 4*x^2 - 25*x^3 - 60*x^4 + 24*x^5 + 72*x^6). - Colin Barker, Oct 03 2018
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EXAMPLE
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Some solutions for n=6.
..1..2..1..1..2..2....0..1..1..2..2..2....1..1..2..0..2..2....1..2..0..2..1..1
..2..0..0..0..1..2....0..1..2..2..2..2....1..2..2..1..1..0....2..1..2..1..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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