On the largest prime factor of non-zero Fourier coefficients of Hecke eigenforms

Fuente: arXiv
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Main Authors: Gun, Sanoli, Naik, Sunil L
Format: Preprint
Published: 2024
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author Gun, Sanoli
Naik, Sunil L
author_facet Gun, Sanoli
Naik, Sunil L
contents Let $τ$ denote the Ramanujan tau function. One is interested in possible prime values of $τ$ function. Since $τ$ is multiplicative and $τ(n)$ is odd if and only if $n$ is an odd square, we only need to consider $τ(p^{2n})$ for primes $p$ and natural numbers $n \geq 1$. This is a rather delicate question. In this direction, we show that for any $ε> 0$ and integer $n \geq 1$, the largest prime factor of $τ(p^{2n})$, denoted by $P(τ(p^{2n}))$, satisfies $$ P(τ(p^{2n})) ~>~ (\log p)^{1/8}(\log\log p)^{3/8 -ε} $$ for almost all primes $p$. This improves a recent work of Bennett, Gherga, Patel and Siksek. Our results are also valid for any non-CM normalized Hecke eigenforms with integer Fourier coefficients.
format Preprint
id arxiv_https___arxiv_org_abs_2402_07944
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle On the largest prime factor of non-zero Fourier coefficients of Hecke eigenforms
Gun, Sanoli
Naik, Sunil L
Number Theory
11F11, 11F30, 11F80, 11N56, 11R45
Let $τ$ denote the Ramanujan tau function. One is interested in possible prime values of $τ$ function. Since $τ$ is multiplicative and $τ(n)$ is odd if and only if $n$ is an odd square, we only need to consider $τ(p^{2n})$ for primes $p$ and natural numbers $n \geq 1$. This is a rather delicate question. In this direction, we show that for any $ε> 0$ and integer $n \geq 1$, the largest prime factor of $τ(p^{2n})$, denoted by $P(τ(p^{2n}))$, satisfies $$ P(τ(p^{2n})) ~>~ (\log p)^{1/8}(\log\log p)^{3/8 -ε} $$ for almost all primes $p$. This improves a recent work of Bennett, Gherga, Patel and Siksek. Our results are also valid for any non-CM normalized Hecke eigenforms with integer Fourier coefficients.
title On the largest prime factor of non-zero Fourier coefficients of Hecke eigenforms
topic Number Theory
11F11, 11F30, 11F80, 11N56, 11R45
url https://arxiv.org/abs/2402.07944