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A299923
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Denominators of successive rational approximations converging to 2*Pi from above for n >= 1, with a(-1) = -1 and a(0) = 0.
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1
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-1, 0, 1, 2, 3, 7, 60, 113, 16664, 33215, 49766, 364913, 1044973, 1725033, 14480324, 27235615, 39990906, 52746197, 65501488, 405764219, 2369083826, 9070571085, 15772058344, 22473545603, 29175032862, 35876520121, 42578007380, 49279494639, 55980981898, 62682469157, 69383956416, 76085443675, 82786930934, 89488418193
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OFFSET
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-1,4
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COMMENTS
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Suggested by Henry Baker in a message to the math-fun mailing list, Mar 16 2018.
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LINKS
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FORMULA
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Set a(-1) = -1; a(0) = 0; a(n+1) = c(n) * a(n) - a(n-1), where t(0) = 2*Pi, c(n) = ceiling (t(n)), and t(n+1) = 1/(c(n) - t(n)).
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EXAMPLE
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The best integer over-estimate of 2*Pi is 7. Between 2*Pi and 7 the rational with the smallest denominator is 13/2. Between 2*Pi and 13/2, the rational with the smallest denominator is 19/3. So a(1) = 1, a(2) = 2, a(3) = 3. [Corrected by Altug Alkan, Mar 19 2018]
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CROSSREFS
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KEYWORD
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frac,sign
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AUTHOR
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EXTENSIONS
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a(-1) = -1 and a(0) = 0 prepended by Altug Alkan, Mar 26 2018
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STATUS
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approved
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