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A234117
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Number of (n+1) X (3+1) 0..2 arrays with every 2 X 2 subblock having the absolute values of all six edge and diagonal differences no larger than 1.
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1
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673, 12593, 231713, 4279065, 79003521, 1458813409, 26937444801, 497411686793, 9184935953377, 169604155276817, 3131820756402657, 57830550281200505, 1067868451774107585, 19718695887361293761, 364115043587212161409
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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) = 20*a(n-1) - 10*a(n-2) - 324*a(n-3) - 277*a(n-4) + 144*a(n-5).
Empirical g.f.: x*(673 - 867*x - 13417*x^2 - 11213*x^3 + 5904*x^4) / (1 - 20*x + 10*x^2 + 324*x^3 + 277*x^4 - 144*x^5). - Colin Barker, Oct 12 2018
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EXAMPLE
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Some solutions for n=2:
..2..2..2..1....1..1..1..0....1..2..2..1....1..1..1..2....2..1..1..2
..2..1..1..1....0..0..0..0....1..1..1..2....0..1..2..1....2..2..1..1
..1..1..2..2....0..0..1..1....1..2..2..2....1..1..2..2....1..1..1..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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