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A275143
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Number of 3 X n 0..2 arrays with no element equal to any value at offset (-2,-2) (-1,-2) or (0,-1) and new values introduced in order 0..2.
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1
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5, 36, 80, 224, 528, 1216, 2816, 6544, 15216, 35376, 82240, 191184, 444448, 1033216, 2401936, 5583824, 12980816, 30176736, 70152400, 163084544, 379125568, 881360016, 2048913456, 4763145904, 11072970816, 25741534096, 59841806560
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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) - 2*a(n-2) + a(n-3) for n>5.
Empirical g.f.: x*(5 + 21*x - 18*x^2 + 51*x^3 - 20*x^4) / (1 - 3*x + 2*x^2 - x^3). - Colin Barker, Feb 01 2019
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EXAMPLE
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Some solutions for n=5:
..0..1..2..1..2. .0..1..2..1..0. .0..1..0..1..2. .0..1..2..0..2
..2..1..2..0..1. .2..1..2..0..1. .2..1..2..0..1. .2..0..2..0..1
..1..2..1..2..1. .2..0..1..0..1. .2..0..1..2..1. .0..2..1..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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