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A211693
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Number of -4..4 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 two, three or four distinct values for every i<=n and j<=n
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1
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80, 712, 6328, 56184, 498328, 4415576, 39087704, 345688344, 3054441560, 26964466456, 237834515800, 2095997626392, 18456488165848, 162389882849432, 1427675316724184, 12542069778534552, 110099840447243864
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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) = 40*a(n-1) -630*a(n-2) +4800*a(n-3) -16675*a(n-4) +13128*a(n-5) +34290*a(n-6) +17120*a(n-7) +3176*a(n-8) +192*a(n-9)
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EXAMPLE
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Some solutions for n=5
.-4...-1...-3...-4...-3...-1...-3...-3...-4...-1...-2...-2...-1...-4...-4...-4
.-3....2...-3....4....2...-3....4....2....0....0...-1....1....1...-1....1...-2
.-3...-2...-2...-2...-1...-1...-2...-4...-4...-2...-4...-4...-4...-3...-2...-2
..2...-3...-3....4....0....4....4...-1....3...-1...-3....0...-1...-2....3....2
.-3...-4....2...-4...-2....4...-4....2...-1...-3...-4...-3....4....0...-1...-2
..2...-3....4....4....1....2...-4...-4....3...-2...-1....2....0....1....2...-4
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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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