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A250463
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Number of (n+1) X (3+1) 0..1 arrays with nondecreasing min(x(i,j),x(i,j-1)) in the i direction and nondecreasing min(x(i,j),x(i-1,j)) in the j direction.
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1
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85, 557, 3476, 21753, 135753, 847278, 5286723, 32988493, 205837420, 1284368485, 8014067309, 50005407550, 312018725543, 1946903634993, 12148095748212, 75800483328529, 472972331775681, 2951205828148958, 18414641259844987
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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) = 5*a(n-1) +14*a(n-2) -35*a(n-3) -37*a(n-4) +68*a(n-5) +30*a(n-6) -44*a(n-7) -8*a(n-8) +8*a(n-9).
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EXAMPLE
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Some solutions for n=5
..0..1..0..0....0..0..1..0....0..0..0..0....0..0..0..0....1..0..0..0
..1..0..1..0....1..0..0..1....0..0..0..0....0..0..0..0....0..0..0..0
..0..0..0..1....0..1..0..0....0..0..1..0....0..0..0..1....1..0..0..1
..1..0..0..0....1..0..0..0....0..1..0..1....0..0..0..0....0..1..0..1
..0..0..0..0....0..0..0..1....0..0..0..0....0..0..0..1....0..0..0..1
..1..1..0..1....0..0..1..0....0..0..1..0....1..0..1..1....1..0..0..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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