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A208388
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Number of n X 4 0..2 arrays with new values 0..2 introduced in row major order and no element equal to more than two of its immediate leftward or upward or right-upward antidiagonal neighbors.
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1
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14, 1017, 76806, 5800644, 438083928, 33085555344, 2498731184736, 188712490047552, 14252194920963456, 1076373164351510784, 81291281473560135168, 6139387958073915884544, 463666998680569442359296
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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) = 76*a(n-1) - 36*a(n-2) for n>3.
Empirical g.f.: x*(14 - 47*x + 18*x^2) / (1 - 76*x + 36*x^2). - Colin Barker, Jul 02 2018
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EXAMPLE
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Some solutions for n=4:
..0..1..2..1....0..0..0..0....0..0..0..0....0..0..0..0....0..1..2..1
..2..2..0..0....0..1..1..0....1..1..0..2....1..2..2..2....2..2..1..2
..0..2..2..0....0..1..0..2....2..0..1..0....1..2..1..1....0..2..2..2
..0..1..0..1....2..2..0..1....1..2..0..2....1..2..1..1....0..0..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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