On a conjecture of Erdős and Graham about the Sylvester's sequence

Fuente: arXiv
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Main Authors: Li, Zheng, Tang, Quanyu
Format: Preprint
Published: 2025
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author Li, Zheng
Tang, Quanyu
author_facet Li, Zheng
Tang, Quanyu
contents Let $\{u_n\}_{n=1}^{\infty}$ be the Sylvester's sequence (sequence A000058 in the OEIS), and let $ a_1 < a_2 < \cdots $ be any other positive integer sequence satisfying $ \sum_{i=1}^\infty \frac{1}{a_i} = 1 $. In this paper, we solve a conjecture of Erdős and Graham, which asks whether $$ \liminf_{n\to\infty} a_n^{\frac{1}{2^n}} < \lim_{n\to\infty} u_n^{\frac{1}{2^n}} = c_0 = 1.264085\ldots. $$ We prove this conjecture using a constructive approach. Furthermore, assuming that the unproven claim of Erdős and Graham that "all rationals have eventually greedy best Egyptian underapproximations" holds, we establish a generalization of this conjecture using a non-constructive approach. [This paper solves Problem 315 on Bloom's website "Erdős problems".]
format Preprint
id arxiv_https___arxiv_org_abs_2503_12277
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle On a conjecture of Erdős and Graham about the Sylvester's sequence
Li, Zheng
Tang, Quanyu
Number Theory
Classical Analysis and ODEs
Primary 11D68, Secondary 11D75, 11P99
Let $\{u_n\}_{n=1}^{\infty}$ be the Sylvester's sequence (sequence A000058 in the OEIS), and let $ a_1 < a_2 < \cdots $ be any other positive integer sequence satisfying $ \sum_{i=1}^\infty \frac{1}{a_i} = 1 $. In this paper, we solve a conjecture of Erdős and Graham, which asks whether $$ \liminf_{n\to\infty} a_n^{\frac{1}{2^n}} < \lim_{n\to\infty} u_n^{\frac{1}{2^n}} = c_0 = 1.264085\ldots. $$ We prove this conjecture using a constructive approach. Furthermore, assuming that the unproven claim of Erdős and Graham that "all rationals have eventually greedy best Egyptian underapproximations" holds, we establish a generalization of this conjecture using a non-constructive approach. [This paper solves Problem 315 on Bloom's website "Erdős problems".]
title On a conjecture of Erdős and Graham about the Sylvester's sequence
topic Number Theory
Classical Analysis and ODEs
Primary 11D68, Secondary 11D75, 11P99
url https://arxiv.org/abs/2503.12277