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A201841
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Number of zero-sum nX2 -1..1 arrays with every element equal to at least one horizontal or vertical neighbor
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1
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1, 5, 25, 97, 411, 1897, 8741, 41689, 201985, 987407, 4891069, 24457873, 123131033, 623695509, 3174983801, 16227954653, 83226630287, 428047598133, 2206766393985, 11399915802567, 58993096946055, 305739808201773, 1586610751415691
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OFFSET
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1,2
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COMMENTS
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Column 2 of A201847
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LINKS
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R. H. Hardin, Table of n, a(n) for n = 1..95
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EXAMPLE
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Some solutions for n=8
.-1.-1...-1..0....1.-1....1..1....1..1...-1..0...-1.-1...-1.-1...-1.-1...-1..0
..1..1...-1..0....1.-1....1.-1....1..0...-1..0....0.-1....1..1...-1.-1...-1..0
..0..1....1..1....1..0....1.-1...-1..0....0..1....0..1....0..1....0..1....0..0
..0..1...-1.-1...-1..0...-1.-1...-1..1....0..1....0..1....0..1....0..1....0..0
.-1..1....1.-1...-1..0....1..1...-1..1....0..0....1..1....0..0....0..0...-1..1
.-1..1....1..1....1..0....0..0....0..0...-1.-1...-1..1....0.-1...-1..1...-1..1
..0.-1....1.-1....1.-1...-1.-1....0..0....0..1...-1..0....0.-1...-1..1....0..0
..0.-1....1.-1....1.-1....0..0...-1.-1....0..1....0..0....0..0....1..1....1..1
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CROSSREFS
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Sequence in context: A055343 A223945 A197085 * A146830 A022729 A098111
Adjacent sequences: A201838 A201839 A201840 * A201842 A201843 A201844
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KEYWORD
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nonn
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AUTHOR
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R. H. Hardin Dec 06 2011
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STATUS
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approved
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