English

A note on $n!$ modulo $p$

Number Theory 2015-05-25 v1

Abstract

Let pp be a prime, ε>0\varepsilon>0 and 0<L+1<L+N<p0<L+1<L+N < p. We prove that if p1/2+ε<N<p1εp^{1/2+\varepsilon}< N <p^{1-\varepsilon}, then #{n! ⁣ ⁣ ⁣(modp);L+1nL+N}>c(NlogN)1/2,c=c(ε)>0. \#\{n!\!\!\! \pmod p;\,\, L+1\le n\le L+N\} > c (N\log N)^{1/2},\,\, c=c(\varepsilon)>0. We use this bound to show that any λ≢0(modp)\lambda\not\equiv 0\pmod p can be represented in the form λn1!...n7!(modp)\lambda \equiv n_1!...n_7!\pmod p, where ni=o(p11/12)n_i=o(p^{11/12}). This slightly refines the previously known range for nin_i.

Keywords

Cite

@article{arxiv.1505.05912,
  title  = {A note on $n!$ modulo $p$},
  author = {M. Z. Garaev and J. Hernández},
  journal= {arXiv preprint arXiv:1505.05912},
  year   = {2015}
}

Comments

9 pages

R2 v1 2026-06-22T09:39:09.861Z