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Prime factors bounded by $k$

Let $S$ be the set of integers with largest prime factor bounded by a given positive integer $k$. Is there a formula for the asymptotic density of such a set $S$?
pallab1234's user avatar
9 votes
2 answers
1k views

On the error term of the Riemann explicit formula

Let: $\rho$ be a non-trivial zero of the Riemann zeta function, $\Lambda$ be the von-Mangoldt function and $\psi(x) =\sum_{n \leq x} \Lambda(n)$. What is the best known upper bound for $$f(x, T) := \...
Q_p's user avatar
  • 1,019
1 vote
0 answers
104 views

Validity of analysis of summation of function of primes using Abel–Plana summation:

Consider the analytic function $g(x)$ Define $$f(x)=g(x)\frac{\sin^2\left(\frac{π\Gamma(x)}{2x}\right)}{\cos^2\left(\frac{π}{2x}\right)}$$ Note that: $$f(p)=g(p) \text{ for prime } p$$ And $f(n)=0$ ...
TPC's user avatar
  • 790
4 votes
0 answers
262 views

Asymptotic number of "modular primes"

We can say that a number $p$ is prime modulo $N$ if for any two numbers $1<a,b<p$, $ab \not\equiv p \pmod N$. We will define $p(n)$ to be the number of primes mod $n$. I'm wondering about the ...
Daniel Weber's user avatar
  • 3,319
9 votes
2 answers
319 views

Representation of a residue modulo prime as a specific product

Let $p$ be a prime number. For every integer $m$, there are integers $u_1$, $u_2$, such that $\lvert u_1\rvert, \lvert u_2\rvert < \sqrt{p}$ and $$m \equiv u_1u_2^{-1} \pmod{p}.$$ Proof of this ...
Denis Shatrov's user avatar
0 votes
0 answers
351 views

On a Duality between Riemann-weil explicit formula and Abel- Plana summation of trigonometric prime counting function:

Consider the analytic function $g(x)$ Now define $f(x)=g(x)\frac{\sin^2\left(\frac{π\Gamma(x)}{2x}\right)}{\cos^2\left(\frac{π}{2x}\right)}$ Such that $|f(x+it)|=o(e^{2πt})$ uniformly for every $x$...
TPC's user avatar
  • 790
2 votes
1 answer
466 views

Number of points on a surface modulo p

I am guessing that the number of solutions $(x_1,x_2,\cdots ,x_s)$ modulo $p$ of the system of polynomials $$x_1x_2\cdots x_s=1,$$ $$(x_1-1)(x_2-1)\cdots (x_s-1)=u$$ where $u$ is non-zero modulo $p$. ...
user avatar
1 vote
0 answers
148 views

Counting prime factors of polynomial functions

Let $\Omega(n)$ denote the number of prime factors (counted with multiplicity) of a non-zero integer $n$. For $f \in \mathbb Z[X]$ non-zero, let $$m(f) = \liminf_{n \to \infty} \Omega(f(n))$$ (1) Is $...
Jens Reinhold's user avatar
-2 votes
2 answers
149 views

Calculate the great common factor between $2^{2n+1}-1$ and $2^{4m+2}+1$ [closed]

How to calculate the great common factor between $2^{2n+1}-1$ and $2^{4m+2}+1$, where $n$ and $m$ are positive numbers. We guess that: the great common factor is $1$.
C. Simon's user avatar
  • 577
3 votes
1 answer
220 views

Bins-and-primes (prime divisors of $\prod(a_i-a_j)$, II)

This is a refined version of a question I have recently posted. For a prime $p$, let $\varphi_p\colon\mathbb Z\to\mathbb Z/p\mathbb Z$ denote the canonical homomorphism from the integers onto the ...
Seva's user avatar
  • 23k
2 votes
1 answer
163 views

Prime divisors of $\prod(a_i-a_j)$

For a prime $p$, let $\varphi_p\colon\mathbb Z\to\mathbb Z/p\mathbb Z$ denote the canonical homomorphism from the integers onto the group of order $p$. Given an integer $n\ge 3$, what is the smallest ...
Seva's user avatar
  • 23k
1 vote
0 answers
55 views

Convergence of Farey series integral of a "density" function as the order tends to infinity

Let $F_n$ denote the $n$-th Farey sequence, and let $q$ be a rational number such that $0 \leq q \leq 1$. I am studying the convergence of a specific integral related to Farey series, defined as ...
swami's user avatar
  • 375
2 votes
1 answer
153 views

Estimating the minimum number of distinct least prime factors found in range of $c$ consecutive integers

When I look at the count of distinct least prime factors for a range of consecutive integers, I am seeing the same minimum number appear again and again. I am wondering if this number represents the ...
Larry Freeman's user avatar
11 votes
2 answers
1k views

Mertens-like theorem

Mertens' first theorem states that $$ \sum_{p \leq n} \frac{\log p}{p} = \log n + O(1). $$ I read in this paper that the following variant is "classical": $$ \sum_{p \leq n} \frac{\log p}{p -...
Charles Bouillaguet's user avatar
3 votes
0 answers
165 views

What is the density of numbers which have at least two divisors whose sum is a perfect square?

Note: This question was posted in MSE about two years ago but it not receive an answer. Hence posting in MO. A positive integer is said to have square-sum divisors if it has at least two divisors ...
Nilotpal Kanti Sinha's user avatar
4 votes
1 answer
515 views

Recent works on the Hardy-Littlewood conjecture on primes represented by quadratic polynomials

I have been working on my master's thesis which is about the equivalence of the Hardy-Littlewood conjecture on primes represented by quadratic polynomials and the Lang-Trotter conjecture for CM ...
Anish Ray's user avatar
  • 309
7 votes
1 answer
481 views

Some conjectures about prime gaps

I checked some relations between primes, here $1<n<10^5$ and $p_n$ is the $n$th prime. $a) p_n^{1/3} - p_{n-1}^{1/3}<1/2$ $b) p_n^{1/n} - p_{n-1}^{1/n}<1/n $ $c) (\log p_n)^{1/2} - (\...
Pinteco's user avatar
  • 521
26 votes
0 answers
567 views

Elliptic analogue of primes of the form $x^2 + 1$

I have a project in mind for an undergraduate to investigate next quarter -- a curiosity really, but I'm surprised I can't find it in the literature. I do not want a detailed analysis here... but ...
Marty's user avatar
  • 13.3k
1 vote
0 answers
63 views

Set from a diophantine equation with similar statistics to primes

While doing some computational calculations with some diophantine equations, I came across with some sequences from solutions of quartic and quintic equations with slowly decreasing frequency, similar ...
rgvalenciaalbornoz's user avatar
3 votes
1 answer
474 views

Curious infinite product, convergence, connection to prime numbers

I have been playing with the following function: $$ f(x)=\frac{\pi x (1-x^2)}{\sin\pi x}\prod_{k=2}^\infty \frac{\sin(\pi x/k)}{\pi x/k} $$ It is hard to get correct numerical values. I'll start with ...
Vincent Granville's user avatar
0 votes
0 answers
101 views

Prime races in two competing arithmetic progressions - error bound

I read an article by Andrew Granville on the subject, there's actually quite a bit of recent literature on the topic. My problem is as follows. I have two sequences of primes: $(p_{1,n})$ and $(p_{3,n}...
Vincent Granville's user avatar
2 votes
2 answers
260 views

Inequalities for two functions related to the primorial function

Added: As remarked in the answers below, my question has a negative (and well-known) answer. We denote by $\mathcal P=\lbrace 2,3,5,7,\ldots\rbrace$ the set of prime-numbers and by $\mathcal P^*=\...
Roland Bacher's user avatar
2 votes
1 answer
140 views

Weak Siegel–Walfisz property

Let $f:\mathbb N \to \mathbb C$ be an arithmetic function. There are various ways to define what the Siegel–Walfisz (S–W) property is for $f(n)$. One simple way is that there exists some function $g(...
Dr. Pi's user avatar
  • 3,062
14 votes
0 answers
297 views

An 'onion-structure' for roots of a series associated to prime numbers?

The series $$\sum_{n=1}^\infty\frac{z^{p_n-n}}{n!}$$ associated to the sequence $p_1=2,p_2=3,p_3=5,p_4=7,p_5=11,\ldots$ of prime numbers defines a holomorphic function in the open disc of radius $e$. ...
Roland Bacher's user avatar
2 votes
0 answers
70 views

Twin prime distribution centering twice a semiprime

What is the conjectured distributional behavior of semiprimes $pq$ ($p$ and $q$ are primes) having the property $2pq+1$ and $2pq-1$ are primes?
Turbo's user avatar
  • 13.9k
1 vote
0 answers
65 views

Distribution of number of prime factors of $p^k\pm1$

What is the behavior of number of prime factors of integers of form $p^k\pm1$ where $p$ is a fixed odd prime or $2$ and $k$ varies over positive integers?
Turbo's user avatar
  • 13.9k
2 votes
0 answers
238 views

Possible regularisation for sum of function of primes

Consider the following sum of function of primes: $$-\sum_{p}\ln\left( 1 - \frac{1}{(ep)^{1/2}} \right){\ln(p)}$$ Here $p$ runs through all primes and $e$ is Euler's constant. We can see that the sum ...
Zaza's user avatar
  • 149
6 votes
0 answers
230 views

A bias for runs in Legendre symbols?

$\newcommand\Legendre[2]{\genfrac(){}{}{#1}{#2}}$An odd prime $p$ defines the sequence $\Legendre1 p,\Legendre2 p,\dotsc,\Legendre{p-1}p$ of values of the Legendre symbol describing the quadratic ...
Roland Bacher's user avatar
13 votes
4 answers
2k views

Proving Mertens' theorem using the prime number theorem

Mertens' Theorem states that $$\sum_{p \leq x}\frac{1}{p} = \log \log x + M + O(1/\log x).$$ This is weaker than the prime number theorem; in fact according to the Wikipedia page, the prime number ...
Daniel Loughran's user avatar
6 votes
1 answer
172 views

Is the set of all solutions $x > 0$ to $ \pi(x) = \operatorname{li}(x)$ unbounded?

Is the set of all solutions $x > 0$ to the equation $\pi(x) = \operatorname{li}(x)$ unbounded? Is $\liminf_{x \to \infty} |\pi(x)-\operatorname{li}(x)|$ equal to $0$? Here, $\pi(x)$ denotes the ...
Jesse Elliott's user avatar
6 votes
2 answers
575 views

Average value of the prime omega function $\Omega$ on predecessors of prime powers

For a positive integer $n$, the prime omega function value $\Omega(n):=\sum_{p\mid n}{\nu_p(n)}$ counts the number of prime divisors of $n$ with multiplicities. A result of Hardy and Wright, [1, ...
Alexander Bors's user avatar
1 vote
1 answer
286 views

GRH and the Euler product

Let $L(\chi, s)$ be the Dirichlet L-Function of a primitive character $\chi$. I believe, if I’m not mistaken, the convergence of the Euler product of $L(\chi, s)$ in the critical strip is known to be ...
edward cornfoot's user avatar
2 votes
1 answer
283 views

Explicit bounds on number of primes of given size

How many prime numbers of $b$ bits are there? Beyond the prime number theorem, one can give explicit bounds on the number of primes below some integer $n$, or in a given interval. For instance, Rosser ...
Bruno's user avatar
  • 456
2 votes
0 answers
352 views

An approximation for the prime counting function

NOTE: I've edited the question one last time, to be much simpler, in the hopes of getting more responses. SETUP: Let $p_n$ denote the $n$th prime, let $p_x = p_{\lceil x \rceil}$ for all $x > 0$, ...
Jesse Elliott's user avatar
10 votes
0 answers
416 views

Are prime numbers among sums of prime numbers distributed as $\frac n{2\ln(n)}$?

Let $(s_n)_{n\in\mathbb N}$ be defined as follows: For $n\in\mathbb N$, $s_n:=2+3+5+\cdots+p_n$ is the sum of the first $n$ prime numbers (e.g.: $s_1=2$, $s_2=5$, $s_3=10$, $s_4=17$, $\ldots$). Let $\...
Tobias Schnieders's user avatar
15 votes
0 answers
365 views

Do primes of the form $4k+1$ ever lead the greatest prime factor race?

Analogous to Chebyshev's race between primes, I examined the race between primes in the greatest prime factors, GPF, of natural numbers. Similar to the regular prime race, in the GPF race, the ...
Nilotpal Kanti Sinha's user avatar
1 vote
0 answers
155 views

Function involving argument of the Riemann zeta function

When $t$ is an ordinate of a zero of Riemann zeta function, we define \begin{equation} f(t):=\frac{t}{2\pi}\log\left(\frac{t}{2\pi e}\right)+S(t)-\frac{1}{8}+\frac{1}{48 \pi t}+\frac{7}{5760 t^3}+...
Steve's user avatar
  • 19
1 vote
1 answer
131 views

Consecutive non-powerful integers

Pair of sequences $\ v_n\ $ and $\ U_n\ $ of integers start as in the following table: [\begin{array}{rrrrrrrrrr} n= & 0 & 1 & 2 & 3 & 4 & 5 & 6 & 7 & \ldots \\ ...
Wlod AA's user avatar
  • 4,786
3 votes
1 answer
293 views

Best available bounds for $\pi(Y)-\pi(Y-X)$?

I don't know much (anything) about sieves, but as I read the section on the Selberg upper bound sieve from Greaves's Sieves in Number Theory, there is a theorem 4 which says that If $Y\ge X \ge 2$, ...
user859588's user avatar
0 votes
2 answers
288 views

Counting powerful integers. Lower bounds

Remark:   The upper bounds are perhaps still more interesting; I may address them in another post. PROBLEM:   Find simple (numerically efficient) lower bounds for the number of powerful integers (...
Wlod AA's user avatar
  • 4,786
7 votes
1 answer
596 views

What consequences would follow from the density hypothesis?

Let $N(\sigma,T)$ denote the number of zeros $\rho=\beta+\gamma i$ of the Riemann zeta function satisfying $\beta\ge \sigma$ and $0<\gamma\le T$, counted with multiplicity. Then the "Density ...
AfterMath's user avatar
  • 435
0 votes
0 answers
68 views

Around similar inequalities than an inequality due to Nicolas, that involve products of consecutive Ramanujan primes

This is cross-posted (and this post is a version to ask just around the veracity of Conjecture 1) as the post with identifier 3594907 and same title), that I've edited on Mathematics Stack Exchange ...
user142929's user avatar
1 vote
1 answer
347 views

On equations with arithmetic functions [closed]

Is this good topic for research: equations with arithmetic functions, for example equations like $\varphi(n)=\sigma(n)$ or $\varphi(n)+\sigma(n)=d(n)$ ? If Anyone here have an advise please tell me ...
Omega's user avatar
  • 31
0 votes
0 answers
136 views

Bounded sums involving primes

I'm trying to generalize the Theorem 2.7.1 in [1] where they prove: $$\sum_{p \leq x} f(p) = \int_{2}^{x} \frac{f(t)}{\log{t}} dt + \epsilon(x)f(x) - \int_{2}^{x} \epsilon(t) f^{'}(t) dt $$ where $\...
Pierluigi's user avatar
  • 109
0 votes
0 answers
169 views

On $\sum_{\rho\in D} \text{dist}(\rho)=\frac{1}{2\pi i} \int_{\partial{D}}\log \zeta(s)\ ds$

Let $D$ denote a closed two dimensional figure as: $D=2+iT\to 2\to 2-\delta\to 2-\delta+i(T-\delta)\to \frac{1}{2}+\epsilon+i(T-\delta)\to\frac{1}{2}+\epsilon\to\frac{1}{2}-\epsilon\to \frac{1}{2}-\...
Honor's user avatar
  • 11
0 votes
0 answers
91 views

Reducing the number of terms in Waring-Goldbach problem by allowing exponents to vary

Assuming the Waring-Goldbach problem (see https://en.m.wikipedia.org/wiki/Waring%E2%80%93Goldbach_problem) has a positive solution, can we reduce the number of terms $t$ to some value $t'$ by allowing ...
Sylvain JULIEN's user avatar
-1 votes
1 answer
243 views

Inversion shift of a Galois radius

Say a non negative $r$ is a Galois radius of $n$ of type $(a,b)$ if $n-r=p^a$ and $n+r=q^b$ with $p$ and $q$ prime and positive $a$ and $b$. If $a\neq b$, say $r$ is "unbalanced" and say $s$ ...
Sylvain JULIEN's user avatar
6 votes
0 answers
465 views

On improvements of the GPY sieve

When $\chi_\mathbb P(n)$ denotes the characteristic function of primes and $\mathcal H=\{h_1,h_2,\dots,h_k\}$ is some admissible $k$-tuple, the GPY sieve can be formulated as follows: $$ S(x)=\sum_{x&...
TravorLZH's user avatar
  • 1,315
-10 votes
1 answer
407 views

Summatory functions for fractional parts

Notation: $$ \{x\}\ :=\ x-\lfloor x\rfloor $$ APF-functions $\ \tau(n)\ $ for $\ 2<n\in\mathbb N,\ $ and $\ \xi(n)\ $ for $\ 3<n\in\mathbb N,\ $ are defined as follows: $$ \tau(n)\ :=\ \sum_{k=...
Wlod AA's user avatar
  • 4,786
4 votes
0 answers
135 views

Average of $\lambda(n+1)$ for $n$ smooth, or smooth-and-rough? What follows?

Let $\lambda$ be the Liouville function, i.e., $\lambda(p_1\dotsb p_k)=(-1)^k$ for $p_1,\dotsc,p_k$ not necessarily distinct. There is a conjecture (due to whom?) that there are infinitely many primes ...
H A Helfgott's user avatar
  • 20.2k

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