On Carmichael and polygonal numbers, Bernoulli polynomials, and sums of base-$p$ digits

Fuente: arXiv
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Auteurs principaux: Kellner, Bernd C., Sondow, Jonathan
Format: Preprint
Publié: 2019
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author Kellner, Bernd C.
Sondow, Jonathan
author_facet Kellner, Bernd C.
Sondow, Jonathan
contents We give a new characterization of the set $\mathcal{C}$ of Carmichael numbers in the context of $p$-adic theory, independently of the classical results of Korselt and Carmichael. The characterization originates from a surprising link to the denominators of the Bernoulli polynomials via the sum-of-base-$p$-digits function. More precisely, we show that such a denominator obeys a triple-product identity, where one factor is connected with a $p$-adically defined subset $\mathcal{S}$ of the squarefree integers that contains $\mathcal{C}$. This leads to the definition of a new subset $\mathcal{C}'$ of $\mathcal{C}$, called the "primary Carmichael numbers". Subsequently, we establish that every Carmichael number equals an explicitly determined polygonal number. Finally, the set $\mathcal{S}$ is covered by modular subsets $\mathcal{S}_d$ ($d \geq 1$) that are related to the Knödel numbers, where $\mathcal{C} = \mathcal{S}_1$ is a special case.
format Preprint
id arxiv_https___arxiv_org_abs_1902_10672
institution arXiv
publishDate 2019
record_format arxiv
spellingShingle On Carmichael and polygonal numbers, Bernoulli polynomials, and sums of base-$p$ digits
Kellner, Bernd C.
Sondow, Jonathan
Number Theory
11B68, 11B83
We give a new characterization of the set $\mathcal{C}$ of Carmichael numbers in the context of $p$-adic theory, independently of the classical results of Korselt and Carmichael. The characterization originates from a surprising link to the denominators of the Bernoulli polynomials via the sum-of-base-$p$-digits function. More precisely, we show that such a denominator obeys a triple-product identity, where one factor is connected with a $p$-adically defined subset $\mathcal{S}$ of the squarefree integers that contains $\mathcal{C}$. This leads to the definition of a new subset $\mathcal{C}'$ of $\mathcal{C}$, called the "primary Carmichael numbers". Subsequently, we establish that every Carmichael number equals an explicitly determined polygonal number. Finally, the set $\mathcal{S}$ is covered by modular subsets $\mathcal{S}_d$ ($d \geq 1$) that are related to the Knödel numbers, where $\mathcal{C} = \mathcal{S}_1$ is a special case.
title On Carmichael and polygonal numbers, Bernoulli polynomials, and sums of base-$p$ digits
topic Number Theory
11B68, 11B83
url https://arxiv.org/abs/1902.10672