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A199905
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Number of -4..4 arrays x(0..n-1) of n elements with zero sum, and adjacent elements not equal modulo three (with -1 modulo 3 = 2).
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1
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1, 6, 42, 152, 804, 5016, 24864, 139148, 814776, 4509164, 25781576, 149525280, 856571710, 4954153908, 28801991844, 167153096856, 973462118580, 5682734337828, 33191217303840, 194193233863080, 1137757795417530
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OFFSET
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1,2
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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....3....1....4...-4....4....1....1....2...-2....3....4...-4...-3....2...-2
..2....1...-1...-3....1...-1....0....2...-2....3...-1...-1....4....2...-2....0
.-2...-4....3...-2...-3....3....2...-2....0...-4...-2...-2...-1....1....0....2
.-4....1....4...-1....1....1...-2....0....2...-3....2...-4....1....0....1....0
..1...-1...-3....3....2...-4...-4...-1....1....2...-3....4...-1....1...-1....4
..3....0...-4...-1....3...-3....3....0...-3....4....1...-1....1...-1....0...-4
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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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