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A252546
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Number of (2+2)X(n+2) 0..3 arrays with every 3X3 subblock row and diagonal sum equal to 1 3 4 6 or 7 and every 3X3 column and antidiagonal sum not equal to 1 3 4 6 or 7
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1
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850, 3880, 15480, 43848, 213120, 881848, 2568432, 12681664, 53297808, 157483872, 782763648, 3314813344, 9868152000, 49199192320, 209132201280, 624968085888, 3120427983360, 13288964395648, 39789382386432, 198807593780224
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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) = 118*a(n-3) -4264*a(n-6) +55168*a(n-9) -225280*a(n-12) +262144*a(n-15) for n>16
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EXAMPLE
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Some solutions for n=4
..3..1..3..3..1..0....3..1..0..3..1..3....3..1..0..3..1..3....2..2..0..2..2..3
..2..2..0..2..2..3....2..2..3..2..2..0....0..0..1..3..0..1....0..2..2..0..2..2
..3..2..2..3..2..2....0..2..2..3..2..2....2..1..1..2..1..1....3..1..3..3..1..0
..3..1..0..0..1..0....3..1..0..3..1..3....0..1..0..0..1..3....2..2..0..2..2..0
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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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