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A220037
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Number of 7 X n arrays of the minimum value of corresponding elements and their horizontal or diagonal neighbors in a random, but sorted with lexicographically nondecreasing rows and nonincreasing columns, 0..1 7 X n array.
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1
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8, 14, 36, 119, 297, 626, 1165, 1963, 3088, 4630, 6711, 9492, 13175, 18010, 24304, 32431, 42843, 56082, 72793, 93738, 119811, 152054, 191674, 240061, 298807, 369726, 454875, 556576, 677439, 820386, 988676, 1185931, 1416163, 1683802, 1993725
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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 - (7/240)*n^5 + (107/144)*n^4 - (209/48)*n^3 + (1609/45)*n^2 + (1913/60)*n - 813 for n>9.
G.f.: x*(8 - 42*x + 106*x^2 - 119*x^3 + 10*x^4 + 108*x^5 - 123*x^6 + 58*x^7 + 36*x^8 - 68*x^9 + 33*x^10 - 10*x^11 - 2*x^12 + 10*x^13 - 3*x^14 - x^15) / (1 - x)^7.
a(n) = 7*a(n-1) - 21*a(n-2) + 35*a(n-3) - 35*a(n-4) + 21*a(n-5) - 7*a(n-6) + a(n-7) for n>16.
(End)
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EXAMPLE
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Some solutions for n=3:
..0..0..0....1..0..0....0..0..0....0..0..0....0..0..0....0..0..0....0..0..0
..0..0..0....1..1..1....1..0..0....1..0..0....0..0..0....1..0..0....0..0..0
..1..0..0....1..1..1....1..0..0....1..1..1....0..0..0....1..0..0....0..0..0
..1..0..0....1..1..1....1..0..0....1..1..1....0..0..0....1..0..0....1..0..0
..1..0..0....1..1..1....1..1..1....1..1..1....0..0..0....1..0..0....1..0..0
..1..1..1....1..1..1....1..1..1....1..1..1....0..0..0....1..1..1....1..0..0
..1..1..1....1..1..1....1..1..1....1..1..1....1..1..0....1..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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