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A275506
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Number of 6 X n 0..2 arrays with no element equal to any value at offset (-2,-1) (-2,0) or (-1,-1) and new values introduced in order 0..2.
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1
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24, 104, 516, 2628, 13384, 68080, 346528, 1763408, 8974288, 45670736, 232422608, 1182818704, 6019467984, 30633598480, 155897059664, 793373760912, 4037548401360, 20547436657936, 104567700792400, 532154167518352
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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) = 3*a(n-1) + 10*a(n-2) + 4*a(n-3) - 4*a(n-4) for n>5.
Empirical g.f.: 4*x*(6 + 8*x - 9*x^2 - 14*x^3 + 5*x^4) / (1 - 3*x - 10*x^2 - 4*x^3 + 4*x^4). - Colin Barker, Feb 04 2019
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EXAMPLE
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Some solutions for n=4:
..0..1..2..0. .0..1..1..1. .0..1..1..1. .0..0..1..0. .0..0..0..1
..1..2..2..0. .1..2..2..0. .1..1..2..2. .0..1..1..2. .1..1..1..1
..2..2..0..1. .1..2..0..0. .1..2..0..0. .1..1..2..2. .2..2..2..2
..2..0..1..1. .2..0..1..1. .2..0..0..1. .1..2..0..0. .0..0..0..0
..0..1..1..2. .2..0..1..2. .0..0..1..1. .2..0..0..1. .0..1..1..1
..0..1..2..2. .0..1..2..0. .0..1..2..2. .0..0..1..1. .2..2..2..2
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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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