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A232303
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Number of n X 2 0..2 arrays with every 0 next to a 1 and every 1 next to a 2 horizontally, vertically or antidiagonally.
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1
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3, 37, 257, 1915, 14223, 105411, 781873, 5798587, 43004317, 318935945, 2365343683, 17542244471, 130099628443, 964865884537, 7155794283827, 53069957831125, 393585996554193, 2918976065097931, 21648181955586463, 160550745032206387
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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) = 6*a(n-1) + 9*a(n-2) + 11*a(n-3) - a(n-4) + 16*a(n-5).
Empirical g.f.: x*(3 + 19*x + 8*x^2 + 7*x^3 + 16*x^4) / (1 - 6*x - 9*x^2 - 11*x^3 + x^4 - 16*x^5). - Colin Barker, Oct 04 2018
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EXAMPLE
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Some solutions for n=6:
..2..1....0..1....2..1....2..2....1..2....1..2....2..1....2..2....0..1....0..2
..0..0....1..2....2..1....1..1....0..2....2..1....0..0....0..0....1..2....1..0
..0..0....2..1....1..1....0..1....1..0....0..1....2..0....1..1....0..2....1..1
..1..1....2..1....2..1....2..2....1..1....0..2....1..0....2..1....2..1....2..1
..2..2....0..2....1..1....2..1....2..0....0..0....1..0....1..0....2..2....0..2
..1..2....1..2....2..1....0..2....1..2....1..2....2..2....2..2....2..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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