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A252274
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Number of (n+2)X(4+2) 0..3 arrays with every 3X3 subblock row and column sum not equal to 2 3 4 6 or 7 and every 3X3 diagonal and antidiagonal sum equal to 2 3 4 6 or 7
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1
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322, 948, 2513, 4895, 15739, 43488, 85808, 276544, 765830, 1513196, 4875644, 13503569, 26685485, 85977789, 238124824, 470585534, 1516162514, 4199176596, 8298487316, 26736562424, 74049808021, 146338582343, 471482312899
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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) = 21*a(n-3) -62*a(n-6) +47*a(n-9) -5*a(n-12) for n>15
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EXAMPLE
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Some solutions for n=4
..3..3..2..3..0..2....3..2..3..3..2..0....2..1..2..2..1..2....2..1..2..2..1..2
..2..2..1..2..2..1....3..2..3..3..2..3....0..2..3..0..2..3....3..2..0..3..2..0
..0..3..2..0..3..2....2..1..2..2..1..2....3..2..3..3..2..3....3..2..3..3..2..3
..3..3..2..3..3..2....3..2..0..3..2..0....2..1..2..2..1..2....2..1..2..2..1..2
..2..2..1..2..2..1....3..2..3..3..2..3....0..2..3..3..2..0....3..2..3..3..2..0
..0..3..2..3..0..2....2..1..2..2..1..2....3..2..3..0..2..3....3..2..3..0..2..3
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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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