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A262473
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Number of (3+1) X (n+1) 0..1 arrays with each row divisible by 3 and each column divisible by 5, read as a binary number with top and left being the most significant bits.
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1
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4, 9, 36, 121, 484, 1849, 7396, 29241, 116964, 466489, 1865956, 7458361, 29833444, 119311929, 477247716, 1908903481, 7635613924, 30542106169, 122168424676, 488672300601, 1954689202404, 7818751217209, 31275004868836, 125099997105721
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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) = 4*a(n-1) + 5*a(n-2) - 20*a(n-3) - 4*a(n-4) + 16*a(n-5).
Empirical g.f.: x*(4 - 7*x - 20*x^2 + 12*x^3 + 16*x^4) / ((1 - x)*(1 + x)*(1 - 2*x)*(1 + 2*x)*(1 - 4*x)). - Colin Barker, Dec 31 2018
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EXAMPLE
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Some solutions for n=4:
..0..1..0..0..1....1..1..1..1..0....1..1..0..1..1....0..0..0..0..0
..1..0..1..0..1....1..1..0..1..1....1..1..0..1..1....1..1..0..1..1
..0..1..0..0..1....1..1..1..1..0....1..1..0..1..1....0..0..0..0..0
..1..0..1..0..1....1..1..0..1..1....1..1..0..1..1....1..1..0..1..1
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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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