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A180158
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Number of ways are there to score a break of n points at snooker. Assuming an infinite number of reds are available, along with the usual six colors, and a break alternates red-color-red-...
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2
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1, 1, 0, 1, 2, 2, 3, 5, 7, 9, 13, 20, 28, 39, 57, 82, 116, 166, 239, 342, 488, 699, 1002, 1433, 2050, 2936, 4203, 6014, 8608, 12323, 17638, 25244, 36134, 51722, 74030, 105961, 151669, 217091, 310729, 444760, 636607, 911202, 1304240, 1866817, 2672058, 3824629
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OFFSET
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0,5
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COMMENTS
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Equivalently, a(n) is the number of compositions of n with odd-indexed parts being 1 and even-indexed parts being between 2 and 7. - Andrew Howroyd, Jan 14 2020
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LINKS
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FORMULA
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a(n) = a(n-3) + a(n-4) + a(n-5) + a(n-6) + a(n-7) + a(n-8) for n >= 8.
G.f.: (1 + x)/(1 - x^3 - x^4 - x^5 - x^6 - x^7 - x^8). - Andrew Howroyd, Jan 14 2020
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EXAMPLE
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For n=0 there is one way to score zero points - pot nothing, potting a single red is the one way to have a break of one, a break of two is impossible (as defined here), a break of three can only be achieved with a red followed by a yellow, ...
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PROG
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(PARI) Vec((1 + x)/(1 - x^3 - x^4 - x^5 - x^6 - x^7 - x^8) + O(x^50)) \\ Andrew Howroyd, Jan 14 2020
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CROSSREFS
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KEYWORD
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nonn,easy
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AUTHOR
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Rob Cummings (robc(AT)rocoto.demon.co.uk), Aug 14 2010
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STATUS
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approved
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