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A250627
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Number of (n+1)X(3+1) 0..2 arrays with nondecreasing 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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585, 2969, 12151, 43185, 134878, 381834, 994281, 2419996, 5560799, 12176364, 25576273, 51841393, 101867368, 194846773, 364006851, 666173582, 1197388373, 2118591655, 3697349343, 6375941481, 10881696630, 18406254608, 30895710373
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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) = 9*a(n-1) -30*a(n-2) +31*a(n-3) +67*a(n-4) -220*a(n-5) +136*a(n-6) +300*a(n-7) -546*a(n-8) +78*a(n-9) +572*a(n-10) -494*a(n-11) -130*a(n-12) +404*a(n-13) -152*a(n-14) -100*a(n-15) +99*a(n-16) -15*a(n-17) -14*a(n-18) +7*a(n-19) -a(n-20)
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EXAMPLE
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Some solutions for n=4
..0..0..1..1....0..0..0..2....0..0..0..1....0..0..1..1....0..0..0..2
..0..0..2..2....0..0..1..1....0..1..1..2....0..0..1..1....0..0..0..2
..0..1..2..2....0..0..1..1....1..1..1..2....0..0..2..1....1..1..2..1
..1..1..2..2....0..0..1..2....2..1..2..1....1..1..1..2....0..2..1..2
..1..2..2..2....0..0..2..2....1..2..1..2....1..2..1..2....1..1..2..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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