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A229406
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Number of n X 2 0..3 arrays avoiding 11 horizontally, 22 vertically, 33 antidiagonally and 00 diagonally.
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1
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15, 163, 1756, 18712, 199595, 2127718, 22684613, 241841143, 2578301479, 27487534672, 293047669224, 3124213038091, 33307577031714, 355095715688893, 3785714221110283, 40359912854042611, 430281439964832908
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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) = 10*a(n-1) + 13*a(n-2) - 67*a(n-3) + 38*a(n-4) - 2*a(n-5).
Empirical g.f.: x*(15 + 13*x - 69*x^2 + 38*x^3 - 2*x^4) / (1 - 10*x - 13*x^2 + 67*x^3 - 38*x^4 + 2*x^5). - Colin Barker, Sep 15 2018
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EXAMPLE
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Some solutions for n=3:
..3..3....3..2....2..3....3..3....1..0....0..2....1..0....1..0....0..2....3..3
..2..2....3..0....1..2....2..0....3..0....3..3....3..2....1..0....1..3....1..3
..1..0....0..1....1..3....3..3....3..0....1..2....2..3....3..1....2..0....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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