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A252258
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Number of (n+2) X (2+2) 0..3 arrays with every 3 X 3 subblock row and column sum not equal to 0 2 3 6 or 7 and every 3 X 3 diagonal and antidiagonal sum equal to 0 2 3 6 or 7.
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1
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1331, 1016, 562, 512, 570, 782, 1178, 1670, 2474, 3890, 5642, 8594, 13922, 20498, 31778, 52418, 77858, 121922, 203138, 303170, 477314, 799490, 1196162, 1888514, 3171842, 4751618, 7512578, 12635138, 18940418, 29967362, 50436098, 75629570
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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) = a(n-1) + 6*a(n-3) - 6*a(n-4) - 8*a(n-6) + 8*a(n-7) for n>12.
Empirical g.f.: x*(1331 - 315*x - 454*x^2 - 8036*x^3 + 1948*x^4 + 2936*x^5 + 11344*x^6 - 2376*x^7 - 4100*x^8 - 1360*x^9 - 736*x^10 - 176*x^11) / ((1 - x)*(1 - 2*x^3)*(1 - 4*x^3)). - Colin Barker, Dec 03 2018
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EXAMPLE
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Some solutions for n=4:
..0..2..2..0....2..2..1..2....1..0..3..2....2..0..2..2....3..3..2..0
..2..3..3..2....0..3..2..3....1..1..2..2....3..2..3..0....2..2..0..2
..2..3..3..2....3..3..2..3....2..3..0..1....3..2..3..3....3..3..2..3
..1..2..2..0....2..2..0..2....1..0..3..2....2..0..2..2....3..3..2..3
..2..3..3..2....3..3..2..3....2..2..1..1....3..2..3..3....2..2..0..2
..2..3..3..2....0..3..2..3....2..3..0..1....3..2..3..0....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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