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A269411
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Number of length-5 0..n arrays with no repeated value greater than or equal to the previous repeated value.
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1
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12, 159, 804, 2670, 6960, 15477, 30744, 56124, 95940, 155595, 241692, 362154, 526344, 745185, 1031280, 1399032, 1864764, 2446839, 3165780, 4044390, 5107872, 6383949, 7902984, 9698100, 11805300, 14263587, 17115084, 20405154, 24182520
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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^5 + 5*n^4 + (11/2)*n^3 + n^2 - (1/2)*n.
G.f.: 3*x*(4 + 29*x + 10*x^2 - 3*x^3) / (1 - x)^6.
a(n) = 6*a(n-1) - 15*a(n-2) + 20*a(n-3) - 15*a(n-4) + 6*a(n-5) - a(n-6) for n>6.
(End)
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EXAMPLE
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Some solutions for n=8:
..0. .0. .2. .0. .2. .2. .6. .6. .3. .5. .8. .1. .5. .4. .2. .0
..5. .5. .8. .1. .3. .5. .0. .3. .8. .6. .7. .2. .0. .2. .3. .8
..8. .3. .6. .1. .0. .1. .5. .6. .7. .6. .0. .3. .5. .5. .0. .1
..4. .0. .7. .0. .2. .5. .0. .5. .1. .7. .7. .4. .7. .6. .7. .8
..5. .7. .0. .5. .3. .4. .4. .2. .7. .5. .8. .7. .7. .8. .8. .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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