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A251134
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Number of (n+1) X (5+1) 0..2 arrays with no 2 X 2 subblock having the sum of its diagonal elements greater than the maximum of its antidiagonal elements.
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1
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2129, 4786, 8050, 14753, 25597, 46023, 82431, 151567, 282371, 536601, 1033153, 2013629, 3956545, 7822675, 15528811, 30912211, 61642567, 123062869, 245854205, 491382289, 982373589, 1964284511, 3928022839, 7855407543, 15710071467
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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>10.
G.f.: x*(2129 - 7988*x + 7011*x^2 + 7381*x^3 - 16776*x^4 + 9606*x^5 - 883*x^6 - 571*x^7 + 21*x^8 + 2*x^9) / ((1 - x)^5*(1 + x)*(1 - 2*x)).
a(n) = (2*(5472+1058*(-1)^n+2809*2^n) + 6142*n + 1759*n^2 + 266*n^3 + 17*n^4) / 12 for n>3.
(End)
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EXAMPLE
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Some solutions for n=4:
..2..0..0..0..0..2....0..0..0..0..0..0....2..2..2..2..2..2....0..0..0..0..0..0
..2..0..0..0..0..2....1..1..1..1..1..1....0..0..0..0..0..0....0..0..0..0..0..0
..2..0..0..0..0..2....0..0..0..0..0..0....2..2..2..2..2..2....0..0..0..0..0..0
..2..0..0..0..0..2....0..0..0..0..0..0....0..0..0..0..0..0....0..0..0..0..0..0
..2..0..0..0..0..0....2..2..1..1..1..1....2..1..1..1..1..0....2..1..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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