Binomial coefficients with divisors avoiding an interval

Fuente: arXiv
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Main Authors: Bui, Hung M., Pratt, Kyle, Zaharescu, Alexandru
Format: Preprint
Published: 2026
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author Bui, Hung M.
Pratt, Kyle
Zaharescu, Alexandru
author_facet Bui, Hung M.
Pratt, Kyle
Zaharescu, Alexandru
contents We investigate a fifty-year-old conjecture of Erdős and Graham concerning whether the binomial coefficient ${n \choose k}$ with $1 \leq k \leq \frac{n}{2}$ must always have a divisor $\leq n$ that is ``close'' to $n$: that is, bigger than a constant times $n$. We show this is the case when $k$ is sufficiently large as a function of $n$. However, we show (under the Generalized Riemann Hypothesis) it is possible to find binomial coefficients ${n \choose k}$, where $k$ is small compared to $n$, such that ${n \choose k}$ does not have divisors $\leq n$ close to $n$. This settles the conjecture of Erdős and Graham, under GRH. This latter, more substantial argument involves a restricted covering problem with residue classes, sieve methods, and various exponential sum estimates.
format Preprint
id arxiv_https___arxiv_org_abs_2605_21221
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle Binomial coefficients with divisors avoiding an interval
Bui, Hung M.
Pratt, Kyle
Zaharescu, Alexandru
Number Theory
We investigate a fifty-year-old conjecture of Erdős and Graham concerning whether the binomial coefficient ${n \choose k}$ with $1 \leq k \leq \frac{n}{2}$ must always have a divisor $\leq n$ that is ``close'' to $n$: that is, bigger than a constant times $n$. We show this is the case when $k$ is sufficiently large as a function of $n$. However, we show (under the Generalized Riemann Hypothesis) it is possible to find binomial coefficients ${n \choose k}$, where $k$ is small compared to $n$, such that ${n \choose k}$ does not have divisors $\leq n$ close to $n$. This settles the conjecture of Erdős and Graham, under GRH. This latter, more substantial argument involves a restricted covering problem with residue classes, sieve methods, and various exponential sum estimates.
title Binomial coefficients with divisors avoiding an interval
topic Number Theory
url https://arxiv.org/abs/2605.21221