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A247527
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Number of length n+3 0..2 arrays with some disjoint pairs in every consecutive four terms having the same sum.
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1
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33, 45, 61, 81, 105, 153, 217, 297, 393, 585, 841, 1161, 1545, 2313, 3337, 4617, 6153, 9225, 13321, 18441, 24585, 36873, 53257, 73737, 98313, 147465, 213001, 294921, 393225, 589833, 851977, 1179657, 1572873, 2359305, 3407881, 4718601, 6291465
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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) + 4*a(n-4) - 4*a(n-5).
Empirical g.f.: x*(33 + 12*x + 16*x^2 + 20*x^3 - 108*x^4) / ((1 - x)*(1 - 2*x^2)*(1 + 2*x^2)). - Colin Barker, Nov 07 2018
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EXAMPLE
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Some solutions for n=6:
..2....1....0....2....0....2....0....0....1....1....0....0....2....1....1....2
..1....0....1....1....1....1....1....1....0....1....2....0....1....2....2....1
..0....2....0....0....0....1....1....1....2....0....1....1....1....0....2....1
..1....1....1....1....1....0....0....0....1....2....1....1....2....1....1....2
..2....1....2....2....2....2....0....0....1....1....2....2....0....1....1....0
..1....0....1....1....1....1....1....1....2....1....2....2....1....2....0....1
..2....2....2....0....2....1....1....1....0....2....1....1....1....0....2....1
..1....1....1....1....1....0....0....0....1....2....1....1....2....1....1....0
..2....1....0....0....2....2....2....0....1....1....0....0....0....1....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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