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A186120
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Number of (n+1) X 2 binary arrays with every 2 X 2 subblock diagonal sum less antidiagonal sum equal to some horizontal or vertical neighbor 2 X 2 subblock diagonal sum less antidiagonal sum.
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1
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0, 14, 18, 50, 74, 182, 298, 678, 1186, 2566, 4690, 9830, 18498, 38006, 72914, 147974, 287554, 579222, 1135282, 2276710, 4488226, 8978102, 17768850, 35496326, 70442882, 140631254, 279616498, 558094758, 1111168738, 2217823222, 4420075090
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OFFSET
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1,2
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COMMENTS
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LINKS
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FORMULA
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Empirical: a(n) = 3*a(n-1) - 6*a(n-3) + 6*a(n-4) - 4*a(n-5) for n>6.
Empirical g.f.: 2*x^2*(7 - 12*x - 2*x^2 + 4*x^3 - 8*x^4) / ((1 - 2*x)*(1 - x - 2*x^2 + 2*x^3 - 2*x^4)). - Colin Barker, Apr 17 2018
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EXAMPLE
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Some solutions for 3 X 2:
..0..1....1..1....1..0....0..0....1..1....0..0....1..0....1..0....0..1....0..1
..0..0....0..0....1..1....1..1....0..0....0..0....0..0....1..0....0..1....1..1
..1..0....1..1....0..1....0..0....0..0....1..1....0..1....1..0....0..1....1..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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