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A252236
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Number of (n+2) X (1+2) 0..3 arrays with every 3 X 3 subblock row and column sum not equal to 1 3 4 6 or 7 and every 3 X 3 diagonal and antidiagonal sum equal to 1 3 4 6 or 7.
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1
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342, 858, 2174, 4708, 13376, 34364, 74824, 213344, 548984, 1196176, 3412160, 8782064, 19136800, 54591872, 140509664, 306184768, 873464576, 2248147904, 4898948224, 13975422464, 35970353024, 78383155456, 223606737920
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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) = 18*a(n-3) - 32*a(n-6) for n>8.
Empirical g.f.: 2*x*(171 + 429*x + 1087*x^2 - 724*x^3 - 1034*x^4 - 2384*x^5 + 512*x^6 + 16*x^7) / ((1 - 2*x^3)*(1 - 16*x^3)). - Colin Barker, Dec 02 2018
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EXAMPLE
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Some solutions for n=4
..3..0..2....1..0..1....1..1..3....0..1..1....3..1..1....0..2..3....2..2..1
..0..3..2....1..3..1....1..1..0....2..3..0....2..0..3....1..3..1....3..0..2
..2..2..1....0..2..0....0..0..2....3..1..1....0..1..1....1..0..1....0..0..2
..0..3..2....1..3..1....1..1..3....0..1..1....0..1..1....3..2..0....2..2..1
..0..3..2....1..3..1....1..1..0....2..3..3....2..3..3....1..0..1....3..0..2
..2..2..1....3..2..3....0..3..2....0..1..1....0..1..1....1..3..1....0..3..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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