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A183685
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Number of (n+1) X 7 binary arrays with every 2 X 2 subblock nonsingular.
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1
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192, 1360, 8704, 58448, 382848, 2542368, 16748160, 110871040, 731709056, 4838473472, 31954317952, 211206670208, 1395251843712, 9220409667200, 60918293373568, 402541765541504, 2659689937121920, 17574356285235840
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OFFSET
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1,1
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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) + 48*a(n-2) - 78*a(n-3) - 720*a(n-4) + 612*a(n-5) + 4232*a(n-6) - 1392*a(n-7) - 8192*a(n-8).
Empirical g.f.: 16*x*(12 + 49*x - 287*x^2 - 1123*x^3 + 2127*x^4 + 8058*x^5 - 4668*x^6 - 17344*x^7) / (1 - 3*x - 48*x^2 + 78*x^3 + 720*x^4 - 612*x^5 - 4232*x^6 + 1392*x^7 + 8192*x^8). - Colin Barker, Apr 04 2018
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EXAMPLE
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Some solutions for 3 X 7:
..0..1..1..1..0..1..1....1..1..1..1..0..1..1....1..1..0..1..0..1..0
..1..1..0..1..1..0..1....1..0..1..0..1..0..1....0..1..1..1..1..0..1
..0..1..1..1..0..1..1....1..1..1..1..1..1..0....1..0..1..0..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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