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A253344
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Number of (n+1) X (2+1) 0..1 arrays with every 2 X 2 subblock diagonal maximum minus antidiagonal maximum nondecreasing horizontally, vertically and ne-to-sw antidiagonally.
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1
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47, 173, 735, 3192, 13917, 60779, 265605, 1161035, 5075841, 22191959, 97027389, 424226867, 1854830841, 8109825551, 35458405365, 155034056747, 677852377137, 2963761021319, 12958396425645, 56657753602595, 247723635757161
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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) = 6*a(n-1) - 5*a(n-2) - 12*a(n-3) + 12*a(n-4) for n>6.
Empirical g.f.: x*(47 - 109*x - 68*x^2 + 211*x^3 - 48*x^4 - 19*x^5) / ((1 - x)*(1 - 2*x)*(1 - 3*x - 6*x^2)). - Colin Barker, Dec 11 2018
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EXAMPLE
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Some solutions for n=4:
..1..1..1....0..1..1....1..1..1....0..1..1....0..1..1....0..1..0....0..0..0
..0..0..0....0..0..1....1..1..1....1..1..0....1..1..0....0..1..1....1..1..1
..1..1..1....1..1..1....1..1..0....0..1..0....1..1..1....0..1..0....0..1..0
..1..0..0....1..1..1....0..1..0....1..1..1....1..1..0....1..1..0....1..1..0
..1..0..1....1..1..0....1..1..1....0..0..1....0..1..1....0..0..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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