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A263907
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Number of (2n+2) X (2+2) 0..1 arrays with each row and column modulo 3 equal to 1, read as a binary number with top and left being the most significant bits.
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1
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16, 528, 14112, 359200, 9024816, 225934128, 5650549312, 141279105600, 3532085249616, 88302884507728, 2207577385564512, 55189471549212000, 1379737047100994416, 34493427986119721328, 862335712313157059712
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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) = 33*a(n-1) - 207*a(n-2) + 175*a(n-3).
G.f.: 16*x / ((1 - x)*(1 - 7*x)*(1 - 25*x)).
a(n) = (3 - 4*7^(1+n) + 25^(1+n)) / 27.
(End)
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EXAMPLE
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Some solutions for n=2:
..1..1..0..1....0..1..1..1....1..0..1..0....1..1..0..1....0..0..0..1
..0..1..1..1....1..1..0..1....1..0..1..0....0..1..0..0....0..1..1..1
..1..0..1..0....1..0..1..0....0..1..0..0....1..1..0..1....0..1..0..0
..1..1..0..1....0..0..0..1....1..0..1..0....0..1..1..1....1..0..1..0
..1..1..0..1....0..0..0..1....0..1..0..0....0..0..0..1....1..0..1..0
..0..1..1..1....1..1..0..1....0..0..0..1....0..1..0..0....1..1..0..1
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CROSSREFS
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Column 2 of A263913 (nonzero terms).
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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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