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Related papers: About Very Perfect Numbers

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We study whether several consecutive prime gaps can all be relatively large at the same time, or is it possible that all are squares or perfect powers, or perhaps none of them are squares? A few related results and problems are also…

Number Theory · Mathematics 2026-02-10 Katalin Gyarmati

We prove that every sufficiently large odd integer is a sum of two positive squares and a prime. Let R(n) be the number of representations n = x^2 + y^2 + p with x, y >= 1 and p prime. We show that R(n) > 0 for all odd n >= n0 and obtain…

General Mathematics · Mathematics 2025-09-19 Ricardo Adonis Caraccioli Abrego

We study the set $\mathcal{S}$ of odd positive integers $n$ with the property ${2n}/{\sigma(n)} - 1 = 1/x$, for positive integer $x$, i.e., the set that relates to odd perfect and odd "spoof perfect" numbers. As a consequence, we find that…

Number Theory · Mathematics 2021-11-29 László Tóth

We introduce the concept of an almost prime number generalizing a prime number. It turns out that a composite almost prime number must be a Carmichael number, in case it exists. We prove several properties of almost prime numbers and…

Number Theory · Mathematics 2026-03-03 Tigran Hakobyan

We prove explicit bounds for the number of sums of consecutive prime squares below a given magnitude.

Number Theory · Mathematics 2021-01-20 Janyarak Tongsomporn , Saeree Wananiyakul , Jörn Steuding

Let $N$ be an odd perfect number. Then, Euler proved that there exist some integers $n, \alpha$ and a prime $q$ such that $N = n^{2}q^{\alpha}$, $q \nmid n$, and $q \equiv \alpha \equiv 1 \bmod 4$. In this note, we prove that the ratio…

Number Theory · Mathematics 2023-12-01 Yoshinosuke Hirakawa

Weird numbers are abundant numbers that are not pseudoperfect. Since their introduction, the existence of odd weird numbers has been an open problem. In this work, we describe our computational effort to search for odd weird numbers, which…

Number Theory · Mathematics 2022-07-27 Wenjie Fang

We prove that every sufficiently large odd integer can be expressed as a sum of one square and fourteen fifth powers, all of primes. In addition, we establish that every sufficiently large even integer can be written as a sum of one square,…

Number Theory · Mathematics 2026-03-09 Geovane Matheus Lemes Andrade

Let $E(N)$ denote the number of positive integers $n \le N$, with $n \equiv 4 \pmod{24}$, which cannot be represented as the sum of four squares of primes. We establish that $E(N)\ll N^{11/32}$, thus improving on an earlier result of Harman…

Number Theory · Mathematics 2016-06-14 Angel V. Kumchev , Lilu Zhao

We create a simple test for distinguishing between sets of primes and random numbers using just the sum-of-digits function. We find that the sum-of-the-digits of prime numbers does not have an equal probability of being odd or even. The…

General Mathematics · Mathematics 2019-01-01 Debayan Gupta , Mayuri Sridhar

We study odd numbers through a straightforward indexing. We focus in particular on odd prime and composite numbers and their distribution. With a counting argument, we calculate the limit of two sums and compare their convergence rate.

General Mathematics · Mathematics 2018-12-11 Wolf Marc , Wolf François , Villemin François-Xavier

We give necessary conditions for perfection of some families of odd numbers with special multiplicative forms. Extending earlier work of Steuerwald, Kanold, McDaniel et al.

Number Theory · Mathematics 2023-04-11 Luis H. Gallardo , Olivier. Rahavandrainy

We present a new topological proof of the infinitude of prime numbers with a new topology. Furthermore, in this topology, we characterize the infinitude of any non-empty subset of prime numbers.

Number Theory · Mathematics 2024-10-30 Jhixon Macías

Among other results, we establish, in a quantitative form, that any sufficiently large integer cannot simultaneously be divisible only by very small primes and have very few digits in its Zeckendorf representation.

Number Theory · Mathematics 2019-09-10 Yann Bugeaud

We study triples {a,b,c} of distinct nonzero rational numbers such that a+1,b+1,c+1,ab+1,ac+1,bc+1 and abc+1 are all perfect squares. We prove that there exist infinitely many such triples. In contrast, we show that no triple of positive…

Number Theory · Mathematics 2026-04-13 Andrej Dujella , Matija Kazalicki , Vinko Petričević

In this paper, we obtain a lower bound for the number of primes $p\leq x$ such that $p-1$ is a sum of two squares and $p+2$ has a bounded number of prime factors. The proof uses the vector sieve framework, involving a semi-linear sieve and…

Number Theory · Mathematics 2025-02-28 Kunjakanan Nath , Likun Xie

We discuss the phenomenon where an element in a number field is not integrally represented by a given positive definite quadratic form, but becomes integrally represented by this form over a totally real extension of odd degree. We prove…

Number Theory · Mathematics 2025-04-17 Nicolas Daans , Vítězslav Kala , Jakub Krásenský , Pavlo Yatsyna

To determine whether a number is congruent or not is an old and difficult topic and progress is slow. The paper presents a new theorem when a prime number is a congruent number or not. The proof is not necessarily any simpler or shorter…

Number Theory · Mathematics 2021-08-03 Jorma Jormakka , Sourangshu Ghosh

In this paper we confirm a conjecture of Sun which states that each positive integer is a sum of a square, an odd square and a triangular number. Given any positive integer m, we show that p=2m+1 is a prime congruent to 3 modulo 4 if and…

Number Theory · Mathematics 2009-02-07 Byeong-Kweon Oh , Zhi-Wei Sun

We shall show that $9$ is the only odd infinitary superperfect numbers.

Number Theory · Mathematics 2017-06-01 Tomohiro Yamada