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A229366
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Number of n X 2 0..2 arrays avoiding 11 horizontally, 22 vertically and 00 antidiagonally.
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1
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8, 38, 184, 869, 4144, 19675, 93589, 444824, 2114934, 10054148, 47798953, 227238276, 1080310539, 5135871337, 24416324712, 116077006646, 551838764656, 2623482504621, 12472231233800, 59293915534091, 281887688707501
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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) = 2*a(n-1) + 13*a(n-2) + 3*a(n-3) - 13*a(n-4) + 4*a(n-5).
Empirical g.f.: x*(8 + 22*x + 4*x^2 - 17*x^3 + 4*x^4) / (1 - 2*x - 13*x^2 - 3*x^3 + 13*x^4 - 4*x^5). - Colin Barker, Sep 14 2018
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EXAMPLE
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Some solutions for n=4:
1 0 0 0 0 2 2 1 2 1 1 0 2 1 0 1 0 1 0 2
1 0 1 0 0 0 0 2 0 1 1 0 0 0 1 2 0 2 2 0
1 0 1 2 1 0 0 0 0 0 2 0 2 0 1 0 1 0 1 0
1 0 2 0 2 0 1 2 2 0 1 2 1 0 2 2 1 2 2 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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