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A229530
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Number of defective 3-colorings of an n X 4 0..2 array connected horizontally, diagonally and antidiagonally with exactly one mistake, and colors introduced in row-major 0..2 order.
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1
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6, 36, 361, 3064, 24344, 185808, 1379512, 10036352, 71892488, 508702512, 3563926872, 24764330720, 170893859240, 1172387842960, 8002259515128, 54379352988992, 368101566941512, 2483167144168432, 16699758317833368
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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) = 14*a(n-1) - 57*a(n-2) + 56*a(n-3) - 16*a(n-4) for n>5.
Empirical g.f.: x*(6 - 48*x + 199*x^2 - 274*x^3 + 105*x^4) / (1 - 7*x + 4*x^2)^2. - Colin Barker, Sep 18 2018
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EXAMPLE
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Some solutions for n=4:
..0..1..0..2....0..1..0..2....0..1..2..1....0..1..0..1....0..1..0..2
..0..1..0..1....0..2..0..1....2..1..0..1....0..2..0..2....0..2..0..1
..0..2..0..1....0..1..0..2....2..1..0..2....1..2..1..0....0..1..2..1
..1..1..0..2....0..1..2..1....0..1..2..1....1..2..1..0....2..1..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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