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A219501
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Number of n X 7 arrays of the minimum value of corresponding elements and their horizontal or vertical neighbors in a random, but sorted with lexicographically nondecreasing rows and nonincreasing columns, 0..1 n X 7 array.
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0
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7, 13, 45, 126, 281, 550, 995, 1703, 2793, 4424, 6804, 10200, 14949, 21470, 30277, 41993, 57365, 77280, 102782, 135090, 175617, 225990, 288071, 363979, 456113, 567176, 700200, 858572, 1046061, 1266846, 1525545, 1827245, 2177533, 2582528
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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) = (1/720)*n^6 + (1/240)*n^5 + (23/144)*n^4 + (13/16)*n^3 + (331/180)*n^2 + (311/60)*n - 27 for n>3.
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EXAMPLE
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Some solutions for n=3
..0..0..0..0..0..0..0....1..0..0..0..0..0..0....1..0..0..0..0..0..0
..1..0..0..0..0..0..0....1..1..0..0..0..0..0....1..1..0..0..0..0..0
..1..1..1..1..1..1..0....1..1..1..1..1..1..0....1..1..1..1..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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