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Timeline for Fibonacci sequence inversion

Current License: CC BY-SA 2.5

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Aug 31, 2023 at 21:30 comment added Тyma Gaidash If one wants, an answer for $n\in\Bbb C$ and all branches can be written in closed form using series solution for general trinomial
Mar 10, 2017 at 9:42 history edited CommunityBot
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Jan 8, 2012 at 12:08 answer added joro timeline score: 2
Mar 10, 2011 at 15:14 vote accept Hernán Eche
Oct 4, 2010 at 16:06 answer added resolvent timeline score: 1
Sep 18, 2010 at 0:47 answer added Victor Miller timeline score: 9
Sep 17, 2010 at 20:21 comment added Sergei Ivanov The logarithm seems inevitable, but you can get rid of the floor function at the expense of some square roots. Just observe that $5F_n^2-2=\varphi^{2n}+\varphi^{-2n}$ and solve a quadratic equation in $\varphi^{2n}$.
Sep 17, 2010 at 20:11 comment added Mikola If a logarithm is distasteful, then you could also just iteratively compute the Fourier series until you find a number which is either greater than or equal to the number you are looking for. By doing this, you would ultimately find the index you want in time proportional to its location in the sequence. Since the Fourier series terms grow exponentially, this algorithm would be polynomial on the size of the input number (in bits), and so it isn't really that inefficient.
Sep 17, 2010 at 19:51 history edited Tony Huynh CC BY-SA 2.5
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Sep 17, 2010 at 19:38 answer added Mark Bennet timeline score: 1
Sep 17, 2010 at 18:57 answer added Michael Lugo timeline score: 2
Sep 17, 2010 at 18:43 comment added Michael Lugo There's a sense in which the logarithm seems inelegant here, I think.
Sep 17, 2010 at 18:20 history edited Charles Matthews CC BY-SA 2.5
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Sep 17, 2010 at 18:08 answer added Charles Matthews timeline score: 3
Sep 17, 2010 at 18:02 comment added Qiaochu Yuan What's wrong with the logarithm?
Sep 17, 2010 at 17:19 history asked Hernán Eche CC BY-SA 2.5