On a problem of Erdös related to common factor differences

2019 ◽  
Vol 15 (05) ◽  
pp. 1059-1068
Author(s):  
Andrew Bremner
Keyword(s):  
Number Theory ◽  
Positive Integer ◽  
Common Factor ◽  
Difference Set ◽  
Acta Arith ◽  
Factor Difference

Let [Formula: see text] be a positive integer. The factor-difference set [Formula: see text] of [Formula: see text] is the set of absolute values [Formula: see text] of the differences between the factors of any factorization of [Formula: see text] as a product of two integers. Erdős and Rosenfeld [The factor–difference set of integers, Acta Arith. 79(4) (1997) 353–359] ask whether for every positive integer [Formula: see text] there exist integers [Formula: see text] such that [Formula: see text], and prove this is true when [Formula: see text]. Urroz [A note on a conjecture of Erdős and Rosenfeld, J. Number Theory 78(1) (1999) 140–143] shows the result true for [Formula: see text]. The ideas of this paper can be extended, and here, we show the result true for [Formula: see text] by proving there are infinitely many sets of four integers with four common factor differences.

A SURVEY OF FACTORIZATION COUNTING FUNCTIONS

2005 ◽  
Vol 01 (04) ◽  
pp. 563-581 ◽  
Author(s):  
A. KNOPFMACHER ◽  
M. E. MAYS
Keyword(s):  
Number Theory ◽  
Positive Integer ◽  
Additive Number Theory ◽  
Recursive Algorithms ◽  
Additive Number ◽  
Combinatorial Objects ◽  
Survey Techniques ◽  
Counting Functions ◽  
General Field ◽  
Positive Integers

The general field of additive number theory considers questions concerning representations of a given positive integer n as a sum of other integers. In particular, partitions treat the sums as unordered combinatorial objects, and compositions treat the sums as ordered. Sometimes the sums are restricted, so that, for example, the summands are distinct, or relatively prime, or all congruent to ±1 modulo 5. In this paper we review work on analogous problems concerning representations of n as a product of positive integers. We survey techniques for enumerating product representations both in the unrestricted case and in the case when the factors are required to be distinct, and both when the product representations are considered as ordered objects and when they are unordered. We offer some new identities and observations for these and related counting functions and derive some new recursive algorithms to generate lists of factorizations with restrictions of various types.

scholarly journals A Ramsey-type property in additive number theory

1985 ◽  
Vol 27 ◽  
pp. 5-10
Author(s):  
S. A. Burr ◽  
P. Erdös
Keyword(s):  
Number Theory ◽  
Positive Integer ◽  
Additive Number Theory ◽  
Additive Number ◽  
Large Positive Integer ◽  
Ramsey Type ◽  
Type Property ◽  
Positive Integers

Let A be a sequence of positive integers. Define P(A) to be the set of all integers representable as a sum of distinct terms of A. Note that if A contains a repeated value, we are free to use it as many times as it occurs in A. We call A complete if every sufficiently large positive integer is in P(A), and entirely complete if every positive integer is in P(A). Completeness properties have received considerable, if somewhat sporadic, attention over the years. See Chapter 6 of [3] for a survey.

scholarly journals On the sum of digits of some sequences of integers

2013 ◽  
Vol 11 (1) ◽  
Author(s):  
Javier Cilleruelo ◽  
Florian Luca ◽  
Juanjo Rué ◽  
Ana Zumalacárregui
Keyword(s):  
Number Theory ◽  
Positive Integer ◽  
Integer Sequences ◽  
Sum Of Digits ◽  
Fixed Positive Integer ◽  
Almost All

AbstractLet b ≥ 2 be a fixed positive integer. We show for a wide variety of sequences {a n}n=1∞ that for almost all n the sum of digits of a n in base b is at least c b log n, where c b is a constant depending on b and on the sequence. Our approach covers several integer sequences arising from number theory and combinatorics.

Number theory and other reminiscences of Viscount Cherwell

1988 ◽  
Vol 42 (2) ◽  
pp. 197-204 ◽  
Keyword(s):  
Number Theory ◽  
Positive Integer ◽  
Fundamental Theorem ◽  
Prime Numbers ◽  
Christ Church ◽  
Active Interest ◽  
Fundamental Theorem Of Arithmetic ◽  
Elegant Proof ◽  
Theory Of Numbers

Lord Cherwell (i) was, of course, a very distinguished ex-perimental physicist but he had (like many others) a considerable active interest in the theory of numbers. I met him in 1930 when Christ Church, Oxford, elected me to a Senior (postgraduate) Scholarship and I migrated there from my original college. Cherwell’s first published work (2) in the theory of numbers was a very simple and elegant proof of the fundamental theorem of arithmetic, that any positive integer can be expressed as a product of prime numbers in just one way (apart from a possible rearrangement of the order of the factors). (A prime is a positive integer greater than 1 whose only factors are 1 and itself.) His proof is by the method of descent (used by Fermat, but not for this problem). Assume the fundamental theorem false and call any number that can be expressed as a product of primes in two or more ways abnormal.

scholarly journals Elementary methods in the theory of numbers

1939 ◽  
Vol 31 ◽  
pp. xvi-xxiii
Author(s):  
S. A. Scott
Keyword(s):  
Number Theory ◽  
Positive Integer ◽  
Exponential Function ◽  
Monotone Sequence ◽  
Binomial Theorem ◽  
Irrational Numbers ◽  
Early Stages ◽  
Elementary Methods ◽  
Usual Notation ◽  
Theory Of Numbers

§ 1. The importance of proving inequalities of an essentially algebraic nature by “elementary” methods has been emphasised by Hardy (Prolegomena to a Chapter on Inequalities), and by Hardy, Littlewood and Polya (Inequalities). The object of this Note is to show how some of the results in the early stages of Number Theory can be obtained by making a minimum appeal to irrational numbers and the notion of a limit. We use the elementary notion of a logarithm to a base “a” > 1, and make no appeal to the exponential function. The Binomial Theorem is only used for a positive integer index. Our minimum appeal rests in the assumption that a bounded monotone sequence tends to a limit. We adopt throughout the usual notation. Finally, it need scarcely be added that the methods employed are not claimed to be new.

scholarly journals Decompositions of Complete Multigraphs into Cyclic Designs

2020 ◽  
Vol 4 (2) ◽  
pp. 80
Author(s):  
Mowafaq Alqadri ◽  
Haslinda Ibrahim ◽  
Sharmila Karim
Keyword(s):  
Positive Integer ◽  
Difference Set ◽  
Cycle System ◽  
The Difference ◽  
Complete Multigraphs

Let  and  be positive integer,  denote a complete multigraph. A decomposition of a graph  is a set of subgraphs of  whose edge sets partition the edge set of . The aim of this paper, is to decompose a complete multigraph  into cyclic -cycle system according to specified conditions. As the main consequence, construction of decomposition of  into cyclic Hamiltonian wheel system, where , is also given. The difference set method is used to construct the desired designs.

scholarly journals Elementary Number Theory Problems. Part II

2021 ◽  
Vol 29 (1) ◽  
pp. 63-68
Author(s):  
Artur Korniłowicz ◽  
Dariusz Surowik
Keyword(s):  
Number Theory ◽  
Positive Integer ◽  
Prime Numbers ◽  
Elementary Number Theory ◽  
Elementary Number ◽  
Composite Number

Summary In this paper problems 14, 15, 29, 30, 34, 78, 83, 97, and 116 from [6] are formalized, using the Mizar formalism [1], [2], [3]. Some properties related to the divisibility of prime numbers were proved. It has been shown that the equation of the form p 2 + 1 = q 2 + r 2, where p, q, r are prime numbers, has at least four solutions and it has been proved that at least five primes can be represented as the sum of two fourth powers of integers. We also proved that for at least one positive integer, the sum of the fourth powers of this number and its successor is a composite number. And finally, it has been shown that there are infinitely many odd numbers k greater than zero such that all numbers of the form 22 n + k (n = 1, 2, . . . ) are composite.

Asymptotic formulas for certain arithmetic functions

2008 ◽  
Vol 58 (3) ◽  
Author(s):  
M. Garaev ◽  
M. Kühleitner ◽  
F. Luca ◽  
W. Nowak
Keyword(s):  
Number Theory ◽  
Positive Integer ◽  
Arithmetic Functions ◽  
Asymptotic Formulas ◽  
Number Of Divisors ◽  
Second Moments

AbstractThis is an extended summary of a talk given by the last named author at the Czecho-Slovake Number Theory Conference 2005, held at Malenovice in September 2005. It surveys some recent results concerning asymptotics for a class of arithmetic functions, including, e.g., the second moments of the number-of-divisors function d(n) and of the function r(n) which counts the number of ways to write a positive integer as a sum of two squares. For the proofs, reference is made to original articles by the authors published elsewhere.

scholarly journals ON NEAR-PERFECT NUMBERS WITH TWO DISTINCT PRIME FACTORS

2013 ◽  
Vol 88 (3) ◽  
pp. 520-524 ◽  
Author(s):  
XIAO-ZHI REN ◽  
YONG-GAO CHEN
Keyword(s):  
Number Theory ◽  
Positive Integer ◽  
Prime Factors ◽  
Perfect Numbers

AbstractRecently, Pollack and Shevelev [‘On perfect and near-perfect numbers’, J. Number Theory 132 (2012), 3037–3046] introduced the concept of near-perfect numbers. A positive integer $n$ is called near-perfect if it is the sum of all but one of its proper divisors. In this paper, we determine all near-perfect numbers with two distinct prime factors.

An Equation Involving the Smarandache Function

2012 ◽  
Vol 204-208 ◽  
pp. 4785-4788
Author(s):  
Bin Chen
Keyword(s):  
Number Theory ◽  
Positive Integer ◽  
Elementary Number Theory ◽  
Euler Function ◽  
Elementary Number ◽  
Integer Solutions

For any Positive Integer N, LetΦ(n)andS(n)Denote the Euler Function and the Smarandache Function of the Integer N.In this Paper, we Use the Elementary Number Theory Methods to Get the Solutions of the Equation Φ(n)=S(nk) if the K=9, and Give its All Positive Integer Solutions.

Sign in / Sign up

Export Citation Format

Share Document