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A251087
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Number of (n+1) X (7+1) 0..2 arrays with no 2 X 2 subblock having the sum of its diagonal elements greater than the absolute difference of its antidiagonal elements.
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1
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3593, 9086, 15411, 28616, 48017, 82898, 139553, 240972, 420611, 755534, 1387095, 2607904, 4990157, 9687898, 18995941, 37513316, 74424559, 148107894, 295305995, 589513112, 1177703721, 2353835426, 4705809161, 9409435196, 18816319547
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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) - 13*a(n-2) + 10*a(n-3) + 5*a(n-4) - 14*a(n-5) + 9*a(n-6) - 2*a(n-7) for n>8.
Empirical g.f.: x*(3593 - 12472*x + 7604*x^2 + 18338*x^3 - 32161*x^4 + 17566*x^5 - 1962*x^6 - 756*x^7) / ((1 - x)^5*(1 + x)*(1 - 2*x)). - Colin Barker, Nov 24 2018
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EXAMPLE
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Some solutions for n=4:
..0..0..0..1..0..0..1..2....1..0..0..2..0..1..0..2....0..1..0..1..0..0..0..2
..0..0..0..1..0..0..0..0....1..0..0..2..0..1..0..1....0..1..0..1..0..0..0..1
..0..0..0..1..0..0..0..0....1..0..0..2..0..1..0..1....0..1..0..1..0..0..0..0
..1..0..0..1..0..0..0..0....1..0..0..2..0..1..0..1....0..1..0..1..0..0..0..0
..2..1..0..1..0..0..0..0....1..0..0..2..0..1..0..0....2..1..0..1..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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