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A233141
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Number of n X 2 0..5 arrays with no element x(i,j) adjacent to value 5-x(i,j) horizontally, antidiagonally or vertically, top left element zero, and 1 appearing before 2 3 and 4, and 2 appearing before 3 in row major order.
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1
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2, 16, 225, 3727, 65120, 1158334, 20726079, 371568349, 6665506622, 119595908140, 2145992981277, 38507882245867, 690993582249116, 12399363162575962, 222497465035339899, 3992554551056534713, 71643481793789018234
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OFFSET
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1,1
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LINKS
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FORMULA
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Empirical: a(n) = 25*a(n-1) - 134*a(n-2) + 134*a(n-3) - 25*a(n-4) +a(n-5).
Empirical g.f.: x*(2 - 34*x + 93*x^2 - 22*x^3 + x^4) / ((1 - x)*(1 - 18*x + x^2)*(1 - 6*x + x^2)). - Colin Barker, Oct 08 2018
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EXAMPLE
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Some solutions for n=5:
..0..1....0..0....0..0....0..1....0..1....0..1....0..0....0..1....0..1....0..1
..2..1....1..1....1..2....2..2....0..1....1..0....1..2....2..0....2..5....0..2
..2..2....2..1....5..4....1..2....0..1....2..0....0..2....2..1....5..5....4..2
..1..2....5..1....3..3....0..1....0..2....4..0....0..0....5..1....2..2....5..2
..2..1....1..0....4..5....3..5....1..1....4..2....3..0....2..1....2..5....2..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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STATUS
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approved
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