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A222337
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Number of n X 4 0..6 arrays with no entry increasing mod 7 by 6 rightwards or downwards, starting with upper left zero.
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2
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216, 178746, 147918906, 122408393436, 101297497221786, 83827445649884946, 69370328359709445996, 57406526220963704077986, 47506035082750189614687546, 39313010520733216994188515036, 32532978041867113135439462852106
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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) = 873*a(n-1) - 38091*a(n-2) + 387974*a(n-3).
Empirical g.f.: 6*x*(36 - 1637*x + 16884*x^2) / (1 - 873*x + 38091*x^2 - 387974*x^3). - Colin Barker, Mar 15 2018
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EXAMPLE
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Some solutions for n=3:
..0..0..2..0....0..2..2..0....0..2..0..0....0..2..0..0....0..2..2..0
..0..3..5..0....0..3..3..0....0..5..3..0....0..0..2..0....0..3..4..0
..0..3..1..1....2..3..3..5....3..3..4..4....3..5..6..3....0..3..0..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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