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A269681
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Number of length-6 0..n arrays with no repeated value differing from the previous repeated value by other than plus or minus one modulo n+1.
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1
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22, 462, 2976, 12390, 39156, 102606, 234912, 485766, 927780, 1662606, 2827776, 4604262, 7224756, 10982670, 16241856, 23447046, 33135012, 45946446, 62638560, 84098406, 111356916, 145603662, 188202336, 240706950, 304878756, 382703886
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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) = n^6 + 6*n^5 + 5*n^4 + 12*n^3 + 6*n^2 + 6 for n>1.
G.f.: 2*x*(11 + 154*x + 102*x^2 + 245*x^3 - 239*x^4 + 126*x^5 - 46*x^6 + 7*x^7) / (1 - x)^7.
a(n) = 7*a(n-1) - 21*a(n-2) + 35*a(n-3) - 35*a(n-4) + 21*a(n-5) - 7*a(n-6) + a(n-7) for n>8.
(End)
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EXAMPLE
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Some solutions for n=3:
..0. .1. .0. .2. .3. .3. .1. .1. .2. .0. .1. .3. .2. .1. .0. .2
..0. .2. .1. .1. .3. .3. .3. .3. .3. .2. .1. .1. .0. .2. .3. .3
..3. .3. .3. .2. .1. .2. .1. .3. .0. .2. .2. .2. .3. .2. .3. .2
..3. .2. .1. .0. .2. .2. .2. .0. .2. .3. .3. .3. .3. .3. .0. .0
..2. .0. .3. .1. .2. .0. .2. .1. .0. .0. .2. .3. .0. .3. .0. .2
..2. .2. .2. .0. .1. .2. .0. .0. .3. .2. .0. .2. .2. .1. .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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