Formulas and algorithms for the length of a Farey sequence

Abstract This paper proves several novel formulas for the length of a Farey sequence of order n. The formulas use different trade-offs between iteration and recurrence and they range from simple to more complex. The paper also describes several iterative algorithms for computing the length of a Fare...

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Autores principales: Vladimir Sukhoy, Alexander Stoytchev
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Lenguaje:EN
Publicado: Nature Portfolio 2021
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Acceso en línea:https://doaj.org/article/1148cd0c5d324973877551f9cf25a9f3
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spelling oai:doaj.org-article:1148cd0c5d324973877551f9cf25a9f32021-11-21T12:23:01ZFormulas and algorithms for the length of a Farey sequence10.1038/s41598-021-99545-w2045-2322https://doaj.org/article/1148cd0c5d324973877551f9cf25a9f32021-11-01T00:00:00Zhttps://doi.org/10.1038/s41598-021-99545-whttps://doaj.org/toc/2045-2322Abstract This paper proves several novel formulas for the length of a Farey sequence of order n. The formulas use different trade-offs between iteration and recurrence and they range from simple to more complex. The paper also describes several iterative algorithms for computing the length of a Farey sequence based on these formulas. The algorithms are presented from the slowest to the fastest in order to explain the improvements in computational techniques from one version to another. The last algorithm in this progression runs in $$O(n^{2/3})$$ O ( n 2 / 3 ) time and uses only  $$O(\sqrt{n})$$ O ( n ) memory, which makes it the most efficient algorithm for computing  $$|F_n|$$ | F n | described to date. With this algorithm we were able to compute the length of the Farey sequence of order  $$10^{18}$$ 10 18 .Vladimir SukhoyAlexander StoytchevNature PortfolioarticleMedicineRScienceQENScientific Reports, Vol 11, Iss 1, Pp 1-18 (2021)
institution DOAJ
collection DOAJ
language EN
topic Medicine
R
Science
Q
spellingShingle Medicine
R
Science
Q
Vladimir Sukhoy
Alexander Stoytchev
Formulas and algorithms for the length of a Farey sequence
description Abstract This paper proves several novel formulas for the length of a Farey sequence of order n. The formulas use different trade-offs between iteration and recurrence and they range from simple to more complex. The paper also describes several iterative algorithms for computing the length of a Farey sequence based on these formulas. The algorithms are presented from the slowest to the fastest in order to explain the improvements in computational techniques from one version to another. The last algorithm in this progression runs in $$O(n^{2/3})$$ O ( n 2 / 3 ) time and uses only  $$O(\sqrt{n})$$ O ( n ) memory, which makes it the most efficient algorithm for computing  $$|F_n|$$ | F n | described to date. With this algorithm we were able to compute the length of the Farey sequence of order  $$10^{18}$$ 10 18 .
format article
author Vladimir Sukhoy
Alexander Stoytchev
author_facet Vladimir Sukhoy
Alexander Stoytchev
author_sort Vladimir Sukhoy
title Formulas and algorithms for the length of a Farey sequence
title_short Formulas and algorithms for the length of a Farey sequence
title_full Formulas and algorithms for the length of a Farey sequence
title_fullStr Formulas and algorithms for the length of a Farey sequence
title_full_unstemmed Formulas and algorithms for the length of a Farey sequence
title_sort formulas and algorithms for the length of a farey sequence
publisher Nature Portfolio
publishDate 2021
url https://doaj.org/article/1148cd0c5d324973877551f9cf25a9f3
work_keys_str_mv AT vladimirsukhoy formulasandalgorithmsforthelengthofafareysequence
AT alexanderstoytchev formulasandalgorithmsforthelengthofafareysequence
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