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A199897
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Number of -7..7 arrays x(0..n-1) of n elements with zero sum, and adjacent elements not both strictly positive and not both strictly negative
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1
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1, 15, 85, 799, 5839, 51395, 406575, 3500269, 28684325, 245319361, 2048301005, 17499467353, 147731409251, 1263413909311, 10741266363733, 92019265611439, 786112365529335, 6747253002120179, 57843127733658007, 497375672047480891
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OFFSET
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1,2
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COMMENTS
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Column 7 of A199898
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LINKS
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R. H. Hardin, Table of n, a(n) for n = 1..200
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EXAMPLE
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Some solutions for n=6
..1....3....2...-6...-4...-2...-7....2...-7....2....5...-6...-3....6....5....0
..0...-4...-5....7....7....0....6...-4....1....0....0....1....0...-2....0....6
.-1....0....6...-4....0....0....0....7...-3....1...-1...-3....0....2...-7...-5
..2....0...-7....2...-1....4...-6...-3....6...-7....0....4....7...-1....2....0
.-3...-2....7...-2....5...-5....0....1...-4....5....2...-3...-7....0...-3...-1
..1....3...-3....3...-7....3....7...-3....7...-1...-6....7....3...-5....3....0
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CROSSREFS
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Sequence in context: A138322 A206170 A177882 * A309922 A302948 A230676
Adjacent sequences: A199894 A199895 A199896 * A199898 A199899 A199900
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KEYWORD
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nonn
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AUTHOR
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R. H. Hardin Nov 11 2011
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STATUS
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approved
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