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A208099
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Number of 4 X n nonnegative integer arrays with new values 0 upwards introduced in row major order and no element equal to any horizontal, diagonal or antidiagonal neighbor (colorings ignoring permutations of colors).
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2
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1, 15, 500, 192328, 235862938, 677352910013, 3773408294000427, 36179066767453804155, 549736601190850705047301, 12463226118187748082979153202, 402612019211536786633308878052340, 17870804510325656079748707416649732732, 1058340866272922899343613575761029687845720
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OFFSET
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0,2
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LINKS
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EXAMPLE
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Some solutions for n=4:
..0..1..0..1....0..1..0..1....0..1..0..1....0..1..0..1....0..1..0..1
..0..1..0..1....0..1..0..2....0..1..0..1....2..1..0..1....2..1..0..1
..0..1..2..1....2..1..0..1....2..1..0..2....0..3..0..1....0..1..2..1
..0..1..3..1....0..1..0..2....0..1..0..1....4..1..0..1....0..1..0..1
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CROSSREFS
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KEYWORD
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nonn
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AUTHOR
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EXTENSIONS
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a(0)=1 prepended and terms a(6) and beyond from Andrew Howroyd, May 18 2020
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STATUS
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approved
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