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A219628
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Number of 2 X n arrays of the minimum value of corresponding elements and their horizontal or antidiagonal neighbors in a random, but sorted with lexicographically nondecreasing rows and columns, 0..2 2 X n array.
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1
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6, 11, 24, 54, 103, 178, 290, 453, 684, 1003, 1433, 2000, 2733, 3664, 4828, 6263, 8010, 10113, 12619, 15578, 19043, 23070, 27718, 33049, 39128, 46023, 53805, 62548, 72329, 83228, 95328, 108715, 123478, 139709, 157503, 176958, 198175, 221258, 246314
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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) = (1/8)*n^4 - (11/12)*n^3 + (63/8)*n^2 - (145/12)*n + 3 for n>3.
G.f.: x*(6 - 19*x + 29*x^2 - 16*x^3 - 7*x^4 + 12*x^5 - x^6 - x^7) / (1 - x)^5.
a(n) = 5*a(n-1) - 10*a(n-2) + 10*a(n-3) - 5*a(n-4) + a(n-5) for n>8.
(End)
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EXAMPLE
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Some solutions for n=3:
..0..0..0....0..0..2....1..1..2....0..0..1....0..0..1....0..0..1....0..0..1
..0..2..2....0..0..2....2..2..2....0..0..1....0..0..0....1..1..1....0..0..2
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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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