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A248837
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Number of length n arrays x(i), i=1..n with x(i) in 0..i and no value appearing more than 3 times
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3
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2, 6, 24, 118, 686, 4598, 34872, 295044, 2753958, 28103804, 311216626, 3716341042, 47597786154, 650812077852, 9461423560788, 145724617925326, 2370293673319292, 40600119927220706, 730458115445479734, 13772063820971722638
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OFFSET
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1,1
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COMMENTS
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LINKS
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EXAMPLE
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Some solutions for n=6
..0....1....0....1....0....0....1....1....1....0....0....0....0....0....0....1
..2....1....0....2....1....1....1....1....1....1....1....0....0....0....1....1
..2....0....0....0....1....1....2....2....0....3....0....2....3....3....2....2
..1....0....3....0....0....1....4....4....1....0....1....1....2....4....4....1
..5....0....2....2....3....4....5....2....2....4....4....0....1....0....5....5
..3....5....3....1....5....2....5....2....5....0....2....5....0....2....0....6
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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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