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A219933
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Number of nX2 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..3 nX2 array
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1
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4, 23, 76, 208, 519, 1212, 2670, 5574, 11076, 21043, 38390, 67522, 114907, 189804, 305172, 478788, 734604, 1104375, 1629592, 2363756, 3375031, 4749316, 6593778, 9040890, 12253020, 16427619, 21803058, 28665166, 37354523, 48274564, 61900552
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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) = (1/20160)*n^8 + (1/1680)*n^7 + (1/1440)*n^6 + (23/240)*n^5 - (613/2880)*n^4 + (211/120)*n^3 + (11149/5040)*n^2 + (61/420)*n
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EXAMPLE
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Some solutions for n=3
..1..1....0..0....2..2....1..2....0..0....1..1....0..0....0..0....0..0....0..1
..1..1....2..1....0..2....1..1....2..1....2..2....1..2....1..1....0..0....0..0
..3..1....3..3....0..0....1..1....2..2....3..3....1..1....3..1....1..1....2..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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