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A269778
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Number of length-6 0..n arrays with every repeated value unequal to the previous repeated value plus one mod n+1.
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1
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40, 624, 3816, 15040, 45600, 115920, 259504, 527616, 994680, 1764400, 2976600, 4814784, 7514416, 11371920, 16754400, 24110080, 33979464, 47007216, 63954760, 85713600, 113319360, 147966544, 191024016, 244051200, 308815000, 387307440
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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 + 15*n^4 + 14*n^3 + 4*n^2.
G.f.: 8*x*(5 + 43*x + 36*x^2 + 4*x^3 + 2*x^4) / (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>7.
(End)
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EXAMPLE
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Some solutions for n=3:
..3. .1. .3. .1. .1. .3. .3. .1. .2. .2. .3. .3. .0. .2. .1. .2
..3. .0. .0. .3. .3. .3. .2. .2. .3. .2. .3. .0. .3. .0. .0. .3
..1. .3. .0. .3. .3. .3. .0. .3. .2. .1. .3. .3. .3. .0. .0. .1
..1. .2. .1. .0. .3. .3. .2. .3. .1. .1. .2. .0. .0. .0. .3. .0
..2. .1. .2. .2. .3. .0. .1. .0. .2. .2. .3. .1. .2. .0. .0. .3
..3. .2. .2. .2. .0. .1. .2. .3. .0. .1. .1. .1. .3. .3. .1. .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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