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A251094
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Number of (n+1) X (2+1) 0..1 arrays with no 2 X 2 subblock having its minimum diagonal element less than its minimum antidiagonal element.
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1
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41, 212, 1109, 5817, 30517, 160086, 839758, 4405079, 23107524, 121214121, 635847599, 3335437865, 17496560104, 91780937840, 481451239589, 2525527648328, 13248049600905, 69494712657097, 364545365754237, 1912279634115658
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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) = 7*a(n-1) - 11*a(n-2) + 10*a(n-3) - 3*a(n-4).
Empirical g.f.: x*(41 - 75*x + 76*x^2 - 24*x^3) / (1 - 7*x + 11*x^2 - 10*x^3 + 3*x^4). - Colin Barker, Nov 25 2018
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EXAMPLE
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Some solutions for n=4:
..0..0..0....0..0..1....1..0..1....1..1..0....1..0..1....1..0..0....0..0..0
..1..0..0....0..0..0....1..0..1....0..1..1....0..0..0....1..0..0....1..1..0
..0..1..1....0..0..1....1..0..0....0..0..0....0..0..1....0..0..0....0..0..0
..0..0..1....1..0..0....0..0..0....1..1..1....1..0..0....1..0..1....1..0..0
..1..0..1....0..1..0....0..1..1....0..0..0....0..1..0....0..0..0....0..0..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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