On the Number of Conjugate Classes of Derangements

The number of conjugate classes of derangements of order n is the same as the number hn of the restricted partitions with every portion greater than 1. It is also equal to the number of isotopy classes of 2×n Latin rectangles. Sometimes the exact value is necessary, while sometimes we need the appro...

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Autores principales: Wen-Wei Li, Zhong-Lin Cheng, Jia-Bao Liu
Formato: article
Lenguaje:EN
Publicado: Hindawi Limited 2021
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Acceso en línea:https://doaj.org/article/d4ba643404bc434583368b34cd223897
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spelling oai:doaj.org-article:d4ba643404bc434583368b34cd2238972021-11-08T02:35:31ZOn the Number of Conjugate Classes of Derangements2314-478510.1155/2021/6023081https://doaj.org/article/d4ba643404bc434583368b34cd2238972021-01-01T00:00:00Zhttp://dx.doi.org/10.1155/2021/6023081https://doaj.org/toc/2314-4785The number of conjugate classes of derangements of order n is the same as the number hn of the restricted partitions with every portion greater than 1. It is also equal to the number of isotopy classes of 2×n Latin rectangles. Sometimes the exact value is necessary, while sometimes we need the approximation value. In this paper, a recursion formula of hn will be obtained and also will some elementary approximation formulae with high accuracy for hn be presented. Although we may obtain the value of hn in some computer algebra system, it is still meaningful to find an efficient way to calculate the approximate value, especially in engineering, since most people are familiar with neither programming nor CAS software. This paper is mainly for the readers who need a simple and practical formula to obtain the approximate value (without writing a program) with more accuracy, such as to compute the value in a pocket science calculator without programming function. Some methods used here can also be applied to find the fitting functions for some types of data obtained in experiments.Wen-Wei LiZhong-Lin ChengJia-Bao LiuHindawi LimitedarticleMathematicsQA1-939ENJournal of Mathematics, Vol 2021 (2021)
institution DOAJ
collection DOAJ
language EN
topic Mathematics
QA1-939
spellingShingle Mathematics
QA1-939
Wen-Wei Li
Zhong-Lin Cheng
Jia-Bao Liu
On the Number of Conjugate Classes of Derangements
description The number of conjugate classes of derangements of order n is the same as the number hn of the restricted partitions with every portion greater than 1. It is also equal to the number of isotopy classes of 2×n Latin rectangles. Sometimes the exact value is necessary, while sometimes we need the approximation value. In this paper, a recursion formula of hn will be obtained and also will some elementary approximation formulae with high accuracy for hn be presented. Although we may obtain the value of hn in some computer algebra system, it is still meaningful to find an efficient way to calculate the approximate value, especially in engineering, since most people are familiar with neither programming nor CAS software. This paper is mainly for the readers who need a simple and practical formula to obtain the approximate value (without writing a program) with more accuracy, such as to compute the value in a pocket science calculator without programming function. Some methods used here can also be applied to find the fitting functions for some types of data obtained in experiments.
format article
author Wen-Wei Li
Zhong-Lin Cheng
Jia-Bao Liu
author_facet Wen-Wei Li
Zhong-Lin Cheng
Jia-Bao Liu
author_sort Wen-Wei Li
title On the Number of Conjugate Classes of Derangements
title_short On the Number of Conjugate Classes of Derangements
title_full On the Number of Conjugate Classes of Derangements
title_fullStr On the Number of Conjugate Classes of Derangements
title_full_unstemmed On the Number of Conjugate Classes of Derangements
title_sort on the number of conjugate classes of derangements
publisher Hindawi Limited
publishDate 2021
url https://doaj.org/article/d4ba643404bc434583368b34cd223897
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