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A252945
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Number of (n+2) X (1+2) 0..2 arrays with every consecutive three elements in every row, column and nw-se diagonal having exactly two distinct values, and new values 0 upwards introduced in row major order.
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1
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198, 747, 2970, 11943, 48024, 193059, 776160, 3120579, 12546540, 50444415, 202816008, 815438907, 3278541276, 13181653431, 52997956416, 213082782147, 856717412004, 3444505073199, 13848925017096, 55680778531323
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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) = 6*a(n-1) - 9*a(n-2) + 4*a(n-3) + 2*a(n-4) - 6*a(n-5) + 4*a(n-6).
Empirical g.f.: 9*x*(22 - 49*x + 30*x^2 + 6*x^3 - 32*x^4 + 24*x^5) / ((1 - x)*(1 - 5*x + 4*x^2 - 2*x^4 + 4*x^5)). - Colin Barker, Dec 07 2018
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EXAMPLE
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Some solutions for n=4:
..0..1..1....0..1..1....0..1..0....0..0..1....0..1..0....0..1..1....0..1..0
..1..0..0....2..2..1....1..0..1....0..0..2....0..2..2....0..1..0....0..1..0
..0..0..1....2..1..2....0..1..1....1..2..1....1..1..2....2..0..0....1..2..1
..1..1..0....0..1..1....0..1..0....0..2..2....1..2..1....2..0..2....1..1..0
..1..0..1....0..0..2....1..2..1....1..0..1....2..1..1....0..2..2....0..1..0
..0..1..1....1..0..1....1..1..0....0..0..2....1..2..2....2..2..1....0..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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