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A253519
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Number of (n+1)X(3+1) 0..2 arrays with every 2X2 subblock diagonal minimum minus antidiagonal minimum nondecreasing horizontally and diagonal maximum minus antidiagonal maximum nondecreasing vertically
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1
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2180, 10706, 30013, 84684, 256914, 791232, 2419612, 7338525, 22126888, 66487395, 199430934, 597738095, 1791132691, 5367324020, 16086064541, 48218959866, 144563723032, 433475686645, 1299938039440, 3898720339161, 11693742463489
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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) = 12*a(n-1) -61*a(n-2) +172*a(n-3) -295*a(n-4) +316*a(n-5) -207*a(n-6) +76*a(n-7) -12*a(n-8) for n>16
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EXAMPLE
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Some solutions for n=4
..1..2..2..0....2..2..2..2....1..2..1..0....0..1..2..0....0..2..2..2
..0..1..2..1....0..0..0..0....0..2..2..1....0..1..2..0....0..0..0..0
..2..2..2..1....2..2..2..2....0..2..2..2....0..1..2..0....0..0..0..0
..2..0..0..0....2..2..2..2....0..2..2..2....2..2..2..2....1..1..1..1
..2..0..0..2....1..1..1..2....1..2..1..2....2..0..0..0....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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