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A219811
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Number of nX3 arrays of the minimum value of corresponding elements and their horizontal, vertical or diagonal neighbors in a random, but sorted with lexicographically nondecreasing rows and nonincreasing columns, 0..2 nX3 array
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1
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6, 15, 62, 169, 414, 987, 2359, 5569, 12737, 27982, 59028, 119947, 235727, 449688, 835225, 1513962, 2683186, 4656429, 7922316, 13228338, 21698084, 34992721, 55530195, 86778791, 133645391, 202983064, 304247572, 450338045, 658663533
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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) = (1/13305600)*n^11 - (1/725760)*n^10 + (1/51840)*n^9 + (1/6048)*n^8 - (5437/1209600)*n^7 + (2519/34560)*n^6 - (1003/3024)*n^5 - (47861/72576)*n^4 + (820873/64800)*n^3 - (230969/10080)*n^2 - (577453/27720)*n + 76 for n>4
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EXAMPLE
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Some solutions for n=3
..0..0..0....0..0..0....1..0..0....0..0..0....0..0..0....2..0..0....0..0..0
..1..0..0....0..0..0....2..0..0....0..0..0....0..0..0....2..2..0....2..0..0
..2..1..0....2..0..0....2..1..0....0..0..0....1..1..1....2..2..2....2..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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