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A233259
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Number of 4 X n 0..5 arrays with no element x(i,j) adjacent to itself or value 5-x(i,j) horizontally or antidiagonally, top left element zero, and 1 appearing before 2 3 and 4, and 2 appearing before 3 in row major order (unlabelled 6-colorings with no clashing color pairs).
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1
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48, 2080, 221696, 23896064, 2647261184, 294517735424, 32835998056448, 3662495243829248, 408547159030366208, 45573786789742641152, 5083813692357704941568, 567106285442412421578752
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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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FORMULA
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Empirical: a(n) = 160*a(n-1) -6144*a(n-2) +86016*a(n-3) -393216*a(n-4) for n>8.
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EXAMPLE
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Some solutions for n=3
..0..1..2....0..1..2....0..1..2....0..1..0....0..1..2....0..1..0....0..1..0
..2..1..0....0..4..3....0..4..0....0..2..4....2..4..3....2..1..3....5..2..1
..5..2..5....0..1..0....0..1..5....4..3..1....2..0..4....2..5..3....4..3..1
..0..2..1....2..1..5....0..3..1....4..5..4....3..0..4....2..1..5....4..2..5
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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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