dorsal/arxiv
View SchemaPowers in prime bases and a problem on central binomial coefficients
| Authors | Sebastian Tim Holdum, Frederik Ravn Klausen, Peter Michael Reichstein Rasmussen |
|---|---|
| Categories | |
| ArXiv ID | 2601.09510vv1 |
| URL | https://arxiv.org/abs/2601.09510 |
| DOI | 10.5281/zenodo.10456626 |
| Journal | Integers 15,(2015), Paper No. A43, |
| License | http://creativecommons.org/licenses/by-sa/4.0/ |
Abstract
It is an open problem whether $ \binom{2n}{n} $ is divisible by 4 or 9 for all $n>256$. In connection with this, we prove that for a fixed uneven $m$ the asymptotic density of $k$'s such that $ m \nmid \binom{2^{k+1}}{2^{k}} $ is 0. To do so we examine numbers of the form $\alpha^{k}$ in base $p$, where $p$ is a prime and $(\alpha, p)=1$. For every $n$ and $a$ we find an upper bound on the number of $k$'s less than $a$ such that $(\alpha^{k})_p$ contains less than $n$ digits greater than $\frac{p}{2}$. This is done by showing that every sequence of the form $\langle \sigma_t, \dots, \sigma_1,\sigma_0 \rangle$, where $0\leq \sigma_i<p$ for $i\geq 1$ and $\sigma_0$ is in the residue class generated by $\alpha$ modulo $p$, occurs at specific places in the representation $(\alpha^k)_p$ as $k$ varies.
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"abstract": "It is an open problem whether $ \\binom{2n}{n} $ is divisible by 4 or 9 for all $n\u003e256$. In connection with this, we prove that for a fixed uneven $m$ the asymptotic density of $k$\u0027s such that $ m \\nmid \\binom{2^{k+1}}{2^{k}} $ is 0. To do so we examine numbers of the form $\\alpha^{k}$ in base $p$, where $p$ is a prime and $(\\alpha, p)=1$. For every $n$ and $a$ we find an upper bound on the number of $k$\u0027s less than $a$ such that $(\\alpha^{k})_p$ contains less than $n$ digits greater than $\\frac{p}{2}$. This is done by showing that every sequence of the form $\\langle \\sigma_t, \\dots, \\sigma_1,\\sigma_0 \\rangle$, where $0\\leq \\sigma_i\u003cp$ for $i\\geq 1$ and $\\sigma_0$ is in the residue class generated by $\\alpha$ modulo $p$, occurs at specific places in the representation $(\\alpha^k)_p$ as $k$ varies.",
"arxiv_id": "2601.09510",
"authors": [
"Sebastian Tim Holdum",
"Frederik Ravn Klausen",
"Peter Michael Reichstein Rasmussen"
],
"categories": [
"math.NT"
],
"doi": "10.5281/zenodo.10456626",
"journal_ref": "Integers 15,(2015), Paper No. A43,",
"license": "http://creativecommons.org/licenses/by-sa/4.0/",
"title": "Powers in prime bases and a problem on central binomial coefficients",
"url": "https://arxiv.org/abs/2601.09510",
"version": "v1"
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