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A211502
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Number of -3..3 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 three or four distinct values for every i<=n and j<=n
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1
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38, 208, 1104, 5816, 30248, 155984, 798008, 4055448, 20491120, 103013824, 515604792, 2570696888, 12773241696, 63275422112, 312609173352, 1540740611240, 7577596595792, 37196939930000, 182282328074520, 891911689935896
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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) = 10*a(n-1) +37*a(n-2) -550*a(n-3) -649*a(n-4) +13442*a(n-5) +11131*a(n-6) -183874*a(n-7) -197258*a(n-8) +1418860*a(n-9) +2192568*a(n-10) -5278112*a(n-11) -11467160*a(n-12) +5231288*a(n-13) +19433444*a(n-14) -4017688*a(n-15) -17551936*a(n-16) +5387696*a(n-17) +8469936*a(n-18) -4963520*a(n-19) -969600*a(n-20) +1662208*a(n-21) -604416*a(n-22) +97792*a(n-23) -6144*a(n-24)
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EXAMPLE
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Some solutions for n=5
..0...-3....1...-3....1....0...-1...-2....1....0....0...-3...-1...-2....1...-1
.-2....0....0....3....2....3....0....0...-2....3...-2...-1...-3....1....2....2
..3...-3....2....2....0...-3...-1...-3....1....2....0...-3....0....3....0...-2
..2...-2...-1...-3....2....0....1....0....2....0....3...-2...-3....1...-2....1
.-2....2....0....0...-1....1...-2...-2....3...-2....0....1...-2....0....2....2
..1...-2....3...-3....0....0....2....3....2....3...-2....3....3...-3...-2....3
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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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