English

On the Elementary Symmetric Functions of $\{1,1/2,\dots,1/n\}\backslash\{1/i\}$

Number Theory 2025-02-26 v1

Abstract

In 1946, P. Erd\H{o}s and I. Niven proved that there are only finitely many positive integers nn for which one or more of the elementary symmetric functions of 1,1/21,1 / 2, ,1/n\cdots, 1 / n are integers. In 2012, Y. Chen and M. Tang proved that if n4n \geqslant 4, then none of the elementary symmetric functions of 1,1/2,,1/n1,1 / 2, \cdots, 1 / n are integers. In this paper, we prove that if n5n \geqslant 5, then none of the elementary symmetric functions of {1,1/2,,1/n}\{1/i}\{1,1 / 2, \cdots, 1 / n\} \backslash\{1 / i\} are integers except for n=i=2n=i=2 and n=i=4n=i=4.

Keywords

Cite

@article{arxiv.2502.18267,
  title  = {On the Elementary Symmetric Functions of $\{1,1/2,\dots,1/n\}\backslash\{1/i\}$},
  author = {Weilin Zhang and Hongjian Li and Sunben Chiu and Pingzhi Yuan},
  journal= {arXiv preprint arXiv:2502.18267},
  year   = {2025}
}