scholarly journals Square-full numbers in short intervals

1991 ◽  
Vol 110 (1) ◽  
pp. 1-3 ◽  
Author(s):  
D. R. Heath-Brown
Keyword(s):  
Positive Integer ◽  
Riemann Hypothesis ◽  
Prime Factor ◽  
Short Interval ◽  
Short Intervals ◽  
Image Position

A positive integer n is called square-full if p2|n for every prime factor p of n. Let Q(x) denote the number of square-full integers up to x. It was shown by Bateman and Grosswald [1] thatBateman and Grosswald also remarked that any improvement in the exponent would imply a ‘quasi-Riemann Hypothesis’ of the type for . Thus (1) is essentially as sharp as one can hope for at present. From (1) it follows that, for the number of square-full integers in a short interval, we havewhen and y = o (x½). (It seems more suggestive) to write the interval as (x, x + x½y]) than (x, x + y], since only intervals of length x½ or more can be of relevance here.)

scholarly journals On sparsely totient numbers

1991 ◽  
Vol 33 (3) ◽  
pp. 350-358
Author(s):  
Glyn Harman
Keyword(s):  
Positive Integer ◽  
Prime Factor ◽  
Multiplicative Structure ◽  
Euler Totient Function ◽  
Image Position

Following Masser and Shiu [6] we say that a positive integer n is sparsely totient ifHere φ is the familiar Euler totient function. We write ℱ for the set of sparsely totient numbers. In [6] several results are proved about the multiplicative structure of ℱ. If we write P(n) for the largest prime factor of n then it was shown (Theorem 2 of [6]) thatand infinitely often

Short intervals containing numbers without large prime factors

1991 ◽  
Vol 109 (1) ◽  
pp. 1-5 ◽  
Author(s):  
Glyn Harman
Keyword(s):  
Number Theory ◽  
Lower Bound ◽  
Riemann Hypothesis ◽  
Short Intervals ◽  
Prime Factors ◽  
Image Position

We denote, as usual, the number of integers not exceeding x having no prime factors greater than y by Ψ(x, y). We also writeThe function Ψ(x, y) is of great interest in number theory and has been studied by many researchers (see [3], [5] and [6] for example). The function Ψ(x, z, y) has also received some attention (see [2], [4–6]). In this paper we shall try to obtain a positive lower bound for Ψ(x, z, y) with y as small as possible when z is about x½ in magnitude. We note that the approach in [5] and [6] allows y to be much smaller than is permissible here, but requires x/z to be smaller than any power of x in [6] (unless some conjecture like the Riemann Hypothesis is assumed), or needs in [5]. The following result was obtained by Balog[1].

scholarly journals On square-full integers in a short interval

1984 ◽  
Vol 25 (1) ◽  
pp. 127-134 ◽  
Author(s):  
P. Shiu
Keyword(s):  
Positive Integer ◽  
Prime Divisor ◽  
Short Interval ◽  
Image Position

A positive integer nis called a square-full integer if p2 divides n whenever p is a prime divisor of n. For x > 1 we denote by Q(x) the number of square-full integers not exceeding x. Bateman and Grosswald [1] proved that

scholarly journals ON THE LARGEST PRIME FACTOR OF THE MERSENNE NUMBERS

2009 ◽  
Vol 79 (3) ◽  
pp. 455-463 ◽  
Author(s):  
KEVIN FORD ◽  
FLORIAN LUCA ◽  
IGOR E. SHPARLINSKI
Keyword(s):  
Positive Integer ◽  
London Math ◽  
Prime Factor ◽  
Precise Form ◽  
Mersenne Numbers ◽  
Image Position ◽  
Lehmer Numbers

AbstractLetP(k) be the largest prime factor of the positive integerk. In this paper, we prove that the seriesis convergent for each constantα<1/2, which gives a more precise form of a result of C. L. Stewart [‘On divisors of Fermat, Fibonacci, Lucas and Lehmer numbers’,Proc. London Math. Soc.35(3) (1977), 425–447].

scholarly journals ON VALUES TAKEN BY THE LARGEST PRIME FACTOR OF SHIFTED PRIMES

2018 ◽  
Vol 107 (1) ◽  
pp. 133-144 ◽  
Author(s):  
JIE WU
Keyword(s):  
Positive Integer ◽  
Prime Factor ◽  
Prime Numbers ◽  
Asymptotic Density ◽  
Nonzero Integer ◽  
Shifted Primes ◽  
Image Position

Denote by$\mathbb{P}$the set of all prime numbers and by$P(n)$the largest prime factor of positive integer$n\geq 1$with the convention$P(1)=1$. In this paper, we prove that, for each$\unicode[STIX]{x1D702}\in (\frac{32}{17},2.1426\cdots \,)$, there is a constant$c(\unicode[STIX]{x1D702})>1$such that, for every fixed nonzero integer$a\in \mathbb{Z}^{\ast }$, the set$$\begin{eqnarray}\{p\in \mathbb{P}:p=P(q-a)\text{ for some prime }q\text{ with }p^{\unicode[STIX]{x1D702}}<q\leq c(\unicode[STIX]{x1D702})p^{\unicode[STIX]{x1D702}}\}\end{eqnarray}$$has relative asymptotic density one in$\mathbb{P}$. This improves a similar result due to Banks and Shparlinski [‘On values taken by the largest prime factor of shifted primes’,J. Aust. Math. Soc.82(2015), 133–147], Theorem 1.1, which requires$\unicode[STIX]{x1D702}\in (\frac{32}{17},2.0606\cdots \,)$in place of$\unicode[STIX]{x1D702}\in (\frac{32}{17},2.1426\cdots \,)$.

The square-full numbers in an interval

1996 ◽  
Vol 119 (2) ◽  
pp. 201-208 ◽  
Author(s):  
M. N. Huxley ◽  
O. Trifonov
Keyword(s):  
Positive Integer ◽  
Prime Factor ◽  
Perfect Squares ◽  
Image Position

A positive integer is square-full if each prime factor occurs to the second power or higher. Each square-full number can be written uniquely as a square times the cube of a square-free number. The perfect squares make up more than three-quarters of the sequence {si} of square-full numbers, so that a pair of consecutive square-full numbers is a pair of consecutive squares at least half the time, with

scholarly journals GENERALIZED D. H. LEHMER PROBLEM OVER SHORT INTERVALS

2010 ◽  
Vol 53 (2) ◽  
pp. 293-299 ◽  
Author(s):  
PING XI ◽  
YUAN YI
Keyword(s):  
Positive Integer ◽  
Asymptotic Formula ◽  
Asymptotic Properties ◽  
Gauss Sums ◽  
Kloosterman Sums ◽  
Short Intervals ◽  
Lehmer Problem ◽  
Consecutive Integers ◽  
Image Position ◽  
Fixed Positive Integer

AbstractLet n ≥ 2 be a fixed positive integer, q ≥ 3 and c, ℓ be integers with (nc, q)=1 and ℓ|n. Suppose and consist of consecutive integers which are coprime to q. We define the cardinality of a set: The main purpose of this paper is to use the estimates of Gauss sums and Kloosterman sums to study the asymptotic properties of N(, , c, n, ℓ; q), and to give an interesting asymptotic formula for it.

scholarly journals ADDITIVE BASES AND NIVEN NUMBERS

2021 ◽  
pp. 1-8
Author(s):  
CARLO SANNA
Keyword(s):  
Positive Integer ◽  
Natural Number ◽  
Riemann Hypothesis ◽  
Additive Basis

Abstract Let $g \geq 2$ be an integer. A natural number is said to be a base-g Niven number if it is divisible by the sum of its base-g digits. Assuming Hooley’s Riemann hypothesis, we prove that the set of base-g Niven numbers is an additive basis, that is, there exists a positive integer $C_g$ such that every natural number is the sum of at most $C_g$ base-g Niven numbers.

scholarly journals The Divisibility of Divisor Functions

1961 ◽  
Vol 5 (1) ◽  
pp. 35-40 ◽  
Author(s):  
R. A. Rankin
Keyword(s):  
Positive Integer ◽  
Divisor Functions ◽  
Image Position ◽  
Positive Integers

For any positive integers n and v letwhere d runs through all the positive divisors of n. For each positive integer k and real x > 1, denote by N(v, k; x) the number of positive integers n ≦ x for which σv(n) is not divisible by k. Then Watson [6] has shown that, when v is odd,as x → ∞; it is assumed here and throughout that v and k are fixed and independent of x. It follows, in particular, that σ (n) is almost always divisible by k. A brief account of the ideas used by Watson will be found in § 10.6 of Hardy's book on Ramanujan [2].

The Distribution Of Totatives

1955 ◽  
Vol 7 ◽  
pp. 347-357 ◽  
Author(s):  
D. H. Lehmer
Keyword(s):  
Positive Integer ◽  
Prime Factors ◽  
Image Position

This paper is concerned with the numbers which are relatively prime to a given positive integerwhere the p's are the distinct prime factors of n. Since these numbers recur periodically with period n, it suffices to study the ϕ(n) numbers ≤n and relatively prime to n.

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