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A211462
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Number of -2..2 arrays x(i) of n+1 elements i=1..n+1 with x(i)+x(j), x(i+1)+x(j+1), -(x(i)+x(j+1)), and -(x(i+1)+x(j)) having one, two or three distinct values for every i<=n and j<=n
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1
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25, 65, 169, 407, 977, 2283, 5313, 12259, 28253, 65023, 149817, 345739, 799821, 1855467, 4317293, 10077003, 23592677, 55403427, 130474345, 308095007, 729314485, 1730363331, 4113892073, 9798957667, 23379161753, 55863031875
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OFFSET
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1,1
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LINKS
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FORMULA
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Empirical: a(n) = 6*a(n-1) -a(n-2) -55*a(n-3) +70*a(n-4) +193*a(n-5) -357*a(n-6) -320*a(n-7) +802*a(n-8) +238*a(n-9) -922*a(n-10) -39*a(n-11) +533*a(n-12) -29*a(n-13) -136*a(n-14) +6*a(n-15) +12*a(n-16)
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EXAMPLE
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Some solutions for n=5
.-1....1....0....2...-2....0...-2....1....0....0...-2...-1....0....0...-1...-2
..0...-1...-2...-2...-1....1....2....0....2....0....0....0....0...-1....1....2
.-1...-1....0....0....0....0...-2....0...-2...-2...-2....0...-2....0....1...-2
..0...-1...-2...-2...-1....1....2...-2....2....2....0...-1....0....0....1....0
..1...-1....2....2....0...-1...-2....0....0...-2...-2....0....0....0...-1....0
..2...-1....2....2...-1...-1...-2...-2....0....0....2....0....1....0...-1...-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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