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A211570
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Number of -2..2 arrays x(i) of n+1 elements i=1..n+1 with set{t,u,v in 0,1}((x[i+t]+x[j+u]+x[k+v])*(-1)^(t+u+v)) having three, four or five distinct values for every i,j,k<=n.
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1
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16, 28, 44, 74, 116, 194, 308, 518, 836, 1418, 2324, 3974, 6596, 11354, 19028, 32918, 55556, 96458, 163604, 284774, 484676, 845114, 1441748, 2516918, 4300676, 7513898, 12852884, 22467974, 38460356, 67256474, 115184468, 201474518, 345160196
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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) = a(n-1) + 5*a(n-2) - 5*a(n-3) - 6*a(n-4) + 6*a(n-5).
Empirical g.f.: 2*x*(8 + 6*x - 32*x^2 - 15*x^3 + 29*x^4) / ((1 - x)*(1 - 2*x^2)*(1 - 3*x^2)). - Colin Barker, Jul 19 2018
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EXAMPLE
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Some solutions for n=5:
.-2....0....0....1....0....2....1....0....1...-1...-1....0....1....0....1...-1
.-1....2...-2....0...-1....1....0....1....0....0...-2...-1....0....2....2....0
..0....0....0....1...-2....0....1....0....1....1...-1....0...-1....0....1...-1
..1...-2...-2....2...-1...-1....2....1....0....0....0....1....0....2....0....0
..2....0....0....1...-2...-2....1....0...-1...-1....1....2...-1....0...-1....1
..1...-2...-2....0...-1...-1....2...-2...-2...-2....2....1...-2...-1....0....0
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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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