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ON THE DENSITY OF INTEGERS OF THE FORM (p−1)2n IN ARITHMETIC PROGRESSIONS

Published online by Cambridge University Press:  01 December 2008

XUE-GONG SUN
Affiliation:
Department of Mathematics, Nanjing Normal University, Nanjing 210097, People’s Republic of China Department of Mathematics and Science, Huai Hai Institute of Technology, Lian Yun Gang 222005, Jiangsu, People’s Republic of China (email: fangjinhui1114@163.com)
JIN-HUI FANG
Affiliation:
Department of Mathematics, Nanjing Normal University, Nanjing 210097, People’s Republic of China
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Abstract

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Erdős and Odlyzko proved that odd integers k such that k2n+1 is prime for some positive integer n have a positive lower density. In this paper, we characterize all arithmetic progressions in which natural numbers that can be expressed in the form (p−1)2n (where p is a prime number) have a positive proportion. We also prove that an arithmetic progression consisting of odd numbers can be obtained from a covering system if and only if those integers in such a progression which can be expressed in the form (p−1)2n have an asymptotic density of zero.

Type
Research Article
Copyright
Copyright © 2009 Australian Mathematical Society

References

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