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6 votes
1 answer
382 views

Uniformity of the distribution of the prime numbers on the prime residue classes (mod $m$)

Given positive integers $m$, $r$ and $n$, let $\pi(m,r,n)$ denote the number of prime numbers $p \leq n$ in the residue class $r$ (mod $m$). Further let $1 = r_1 < r_2 < \dots < r_{\varphi(m)}...
Stefan Kohl's user avatar
  • 19.6k
6 votes
3 answers
2k views

Better error bounds for partial sums of reciprocals of primes?

One of Mertens' theorems gives that $$\sum_{ p \text{ prime,} p \leq k } 1/p - \log{\log{k}} = B + E(k)$$ where $B$ is a constant near $0.26$ in value and $E(k)$ is an error term whose size is ...
Gerhard Paseman's user avatar
6 votes
1 answer
826 views

Analogue of van der Corput sequence for prime numbers

A van der Corput sequence is a low-discrepancy sequence over the unit interval first published in 1935 by the Dutch mathematician J. G. van der Corput. It is constructed by placing a decimal point and ...
user20174's user avatar
  • 459
6 votes
1 answer
903 views

How to explain this prime gap bias around last digits?

My question is related to this article by Oliver and Soundararajan (article about a bias in the distribution of the last digits of consecutive prime numbers). After trying some python experimental ...
Thierry Boulord's user avatar
6 votes
2 answers
411 views

A simultaneous generalization of the Grunwald-Wang and Dirichlet Theorems on primes

By Grunwald-Wang Theorem, if for some odd number $n$ the equation $x^n=a$ has no solutions in $\mathbb Z$, then the equation $x^n=a\mod p$ has no solutions for some prime number $p$. I am interested ...
Taras Banakh's user avatar
  • 41.8k
6 votes
2 answers
1k views

The shortest interval for which the prime number theorem holds [closed]

It is well known that the prime number theorem on the form \begin{align*} \pi(x+y) - \pi(x) \sim \frac{y}{\log (x+y)} \end{align*} breaks down for short enough intervals, e.g. taking $y=(\log x)^\...
user45947's user avatar
  • 965
6 votes
1 answer
727 views

When does Merten's product theorem accurately estimate the number of coprimes in an interval?

Assume an arbitrary $x$ and let $z$ be smaller than $y$, where $y$ is the length of the interval $[x,x+y]$. What I would like to know is: Let $W(z)=\prod_{p\leq z}\left(1-\frac{1}{p}\right)$. For ...
user45947's user avatar
  • 965
6 votes
1 answer
665 views

On the distribution of roots modulo primes of an integral polynomial

For motivation and related questions, see below. Rough sketch of the question. View $\bigsqcup_{p \text{ prime}} (\mathbb{Z}/p\mathbb{Z})$ as a ‘subset’ of the unit circle, via $a\pmod{p} \mapsto e^{...
user98708's user avatar
6 votes
1 answer
576 views

Other implications of Zhang's method

I have been reading a bit about Zhang's proof and the associated Polymath8 project. Though Tao's high level summary http://terrytao.wordpress.com/2013/06/30/bounded-gaps-between-primes-polymath8-a-...
wood's user avatar
  • 2,810
6 votes
2 answers
837 views

A generalization of strong primes

In this post we denote the sequence of prime numbers as $p_k$ for integers $k\geq 1$. I don't know if the following definition is in the literature. Definition. We define the $\theta$-strong primes, ...
user142929'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
1 answer
233 views

Is there a connection between the average 'compositeness' of a rational number and $\phi$ (golden ratio)?

Let $n\in N$, where $n = p_{1}^{k_{1}}p_{2}^{k_{2}}...p_{m}^{k_{m}}$ for $p_{i}$ prime. Define the 'density' of $n$ as: $d(n) = \frac{(p_{1}+1)^{k_{1}}(p_{2}+1)^{k_{2}}...(p_{m}+1)^{k_{m}}}{n}$ ...
swami's user avatar
  • 375
6 votes
1 answer
826 views

Going beyond the Sylvester and Schur theorem with regard to $x,x+1,\dots,x+n-1$

I was recent reading through Paul Erdos's classic elementary proof of Sylvester-Schur. It occurred me that there is a simple argument that when $x$ is sufficiently large and if $p_i$ represents the $...
Larry Freeman's user avatar
6 votes
4 answers
845 views

Uniform upper bound for the sum over primes $\sum_{p \leq x} p^{-1+\varepsilon}$

I am reading the article D. M. Gordon and C. Pomerance, The distribution of Lucas and elliptic pseudoprime, Math. Comp. (1991) (click). In equation (27) the authors, apparently, used the following ...
user avatar
6 votes
1 answer
367 views

Bounds re Asymptotic Formula for the Sum of Largest Prime Factors

I have a reference request related to the result : $\sum_{n=2}^{x} P(n)$ ~ $\frac{\pi^2}{12}\frac{x^{2}}{log(x)}$ as $x \rightarrow \infty$ where $P(n)$ is the largest prime factor of the positive ...
gjh's user avatar
  • 71
6 votes
1 answer
653 views

On permuted sum of squares of primes in a list

We want to pick a set of distinct primes (if not possible, then just positive numbers) $p_1,p_2,\dots,p_k$ such that there exists $t$ permutations, $\sigma_1(\cdot)$,$\sigma_2(\cdot),\dots,\sigma_t(\...
Turbo's user avatar
  • 13.9k
6 votes
1 answer
499 views

Understanding Sylvester' s $1871$ paper of primes in arithmetic progression of the forms $4n+3$ and $6n+5$

The following is the proof of infinitude of primes in arithmetic progression of the form $4n+3$ and $ 6n+5$ done by Sylvester in $1871$ in his paper "On the theorem that an arithmetical progression ...
math is fun's user avatar
6 votes
1 answer
328 views

Reference Request for a result on divisors of $p-1$

I have seen this result in several places without an English reference: There exist infinitely many primes $p$ such that $p-1=2q_1q_2$ where $q_1$ and $q_2$ are prime numbers with $q_1,q_2>p^{1/4}$...
Marco's user avatar
  • 537
6 votes
1 answer
246 views

The L-function of Q(-1/2) and the "number of prime $p\equiv 3$ divisors" function

In the framework of classical motives, there is no such thing as a motive $\mathbb Q(-\tfrac 12)$, i.e. a tensor root of $\mathbb Q(-1)$. There is one, however, in a more general setting of "...
Xandi Tuni's user avatar
  • 4,015
6 votes
1 answer
481 views

Probabilistic Proofs of Key Number-Theoretic Results

Given a positive integer $n$, let $p$ be the largest prime less than or equal to $n$. Let $N(n)=2^{C_2}\cdots p^{C_p}$ be uniformly distributed from $1$ to $n$, and $M(n)=2^{Z_2}\cdots p^{Z_p}$ where ...
The Substitute's user avatar
6 votes
1 answer
350 views

Counting smooth numbers in short intervals

I am reading a few papers about counting smooth numbers in the interval $[x, x+\sqrt{x}]$, including the work of Harman, and Matomaki. Both authors mentioned that the Dirichlet polynomial techniques ...
user112214's user avatar
6 votes
2 answers
319 views

Evolution of partial sum of a sequence of induced Dirichlet characters

Let's consider the Dirichlet Character $\chi_3(n)$ modulo 3 given by $\chi_3(1)=1$, $\chi_3(2)=-1$ and $\chi_3(3)=\chi_3(0)=0$. Lets consider the sequence of induced characters $\chi^{P_N} $ obtained ...
Bertrand's user avatar
  • 1,199
6 votes
0 answers
381 views

A possible variant of Zagier's one-sentence proof for Fermat's sum of two squares theorem?

Is it possible to modify Zagier's one-sentence proof of Fermat's sum of two squares theorem (see here) to prove certain non-trivial cases of Jacobi's four-square theorem (see here)? Let $p$ be a prime ...
Mathew's user avatar
  • 81
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
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
6 votes
0 answers
149 views

Dickson's conjecture for Beatty sequences

A particular case of Dickson's Conjecture states that for $a_1,q_1,a_2,q_2$ with $(a_1,q_1)=(a_2,q_2)=1$, there are infinitely many $n$ for which $q_1 n + a_1$ and $q_2 n+a_2$ are both prime, provided ...
Joshua Stucky's user avatar
6 votes
0 answers
654 views

Generalized prime number theorem and Riemann Hypothesis for non-number math objects

My question is about some math objects (matrices, polynomials) and operators that satisfy a number of properties which can lead to a theory similar to PNT, RH, Dirichlet functions, abscissa of ...
Vincent Granville's user avatar
6 votes
0 answers
201 views

Smooth integers with lower bound on $\omega(n)$

Define $(b,c)$-smooth integers to be integers having all prime factors bigger than $c$ and smaller than $b$. Probability a number is $(b,1)$-smooth is governed by the Dickman function while ...
VS.'s user avatar
  • 1,826
6 votes
0 answers
435 views

Average value of $\prod_{p|d}{p-1\over p-2}$ for $d=nq$, $n\in{\mathbb N}$, with $p$ odd prime

$\newcommand{\mean}{\mathop{\mathrm{mean}}}$ Define $$ S(d) = \prod_{p|d\atop p>2}{p-1\over p-2}. $$ Bombieri and Davenport (1966) proved that $$ \mean\limits_{d\in{\mathbb N}} S(d) = \mean\...
Alex's user avatar
  • 345
6 votes
0 answers
211 views

some problems on sum of two squares

During my experiments with "Mathematica" I arrived to the following observations. My question is that are they interesting, known, solved or not. If they are known could you please give me a reference....
asad's user avatar
  • 841
6 votes
0 answers
257 views

Convergence with the recurrence $T_{n+1}=T_n^2-T_n+\frac{n}{p_n}$

For each integer $n\geq 1$ I define the recurrence $$T_{n+1}=T_n^2-T_n+\frac{n}{p_n},$$ with $T_1=1$, where $p_k$ denotes the $k$-th prime. So multiplying by $(-1)^n$ and telescoping gives that for ...
user142929's user avatar
6 votes
0 answers
206 views

Primes $p\in(n,2n)$ with $(\frac{-n}p)=-1$

Bertrand's postulate proved by Chebyshev states that for any $x>1$ there is a prime $p$ in the interval $(x,2x)$. In 2012 I considered some refinements of this by imposing additional requirement ...
Zhi-Wei Sun's user avatar
  • 15.6k
6 votes
0 answers
255 views

Gaussian square-free moat

Is there a sequence $\{z_n\}_{n=1}^\infty$ of distinct square-free Gaussian integers with $$\sup_{n \geq 1} |z_{n+1} - z_n| < \infty ?$$ For the analogous problem with Gaussian primes instead, ...
Pablo's user avatar
  • 11.3k
6 votes
0 answers
233 views

admissible tuples vs. prime tuples

Let $\rho^\ast(x)$ denote the maximal length of an admissible sequence in $[1,x]$, i.e. of a sequence which does not cover all the residue classes modulo any $n\geq 2$. Hensley and Richards (1974) ...
GH from MO's user avatar
  • 105k
6 votes
0 answers
505 views

$x^2+1$ attaining almost prime values

Iwaniec, using the linear sieve, proved that $n^2+1$ can be a product of at most two primes infinitely often and furthermore a lower bound of the correct order of magnitude for the number of such ...
Dr. Pi's user avatar
  • 3,062
6 votes
1 answer
1k views

Arguments for the second Hardy–Littlewood conjecture being false?

Assume that $x,y > 2$, and that $x<y$. Then the second Hardy–Littlewood conjecture states that $$\pi(x + y) - \pi(y) \leq \pi(x).$$ We can easily justify this heuristically, since $$ \textrm{...
user45947's user avatar
  • 965
5 votes
3 answers
3k views

Asymptotics of Product of consecutive primes

I am looking for the asymptotic growth of product of consecutive primes. Is there anything that is known about this growth?
Turbo's user avatar
  • 13.9k
5 votes
2 answers
794 views

Is the result of Schmidt conditional to RH

From this page: https://en.wikipedia.org/wiki/Chebyshev_function#Asymptotics_and_bounds A theorem due to Erhard Schmidt states that, for some explicit positive constant $K$, there are infinitely ...
Safwane's user avatar
  • 1,197
5 votes
1 answer
750 views

Geometric mean of prime factors of all numbers up to n

Through numerical calculations I have discovered that for any natural number $n \geq 2$, the geometric mean of the prime factors of all natural numbers $\leq n$ can be approximated well by $1.6653 \...
Marcos Cramer's user avatar
5 votes
2 answers
1k views

A question regarding Cramér's proof on prime gaps under the Riemann Hypothesis

Let $p_n$ be the $n$th prime. Assuming the Riemann hypothesis, Harald Cramér proves that $p_n-p_{n-1}\le C(\sqrt p_n \log p_n)$ for sufficiently large $n$. Is there a value known for the constant $C$ ...
EGME's user avatar
  • 1,018
5 votes
3 answers
2k views

Goldbach conjecture and other problems in additive combinatorics

The field is also known as additive number theory. I am interested in sums $z=x + y$ where $x \in S, y\in T$, and both $S, T$ are infinite sets of positive integers. For instance: $S = T$ is the set ...
Vincent Granville's user avatar
5 votes
2 answers
1k views

Error term in Mertens' third theorem

Mertens' third theorem states that: $$\prod_{\substack{ p \leq x \\ \text{p prime} }} \left( 1 - \dfrac{1}{p} \right) \sim \dfrac{e^{-\gamma}}{\log(x)}$$ Question: what is the best functions (...
Lagrida Yassine's user avatar
5 votes
2 answers
435 views

Proving certain inequality related to Primes

I was reading the following paper. But I can't understand why the last line concerning $\frac{2}{\pi}$ is true. The proof is a work of Sylvester. I would be happy if someone helps me in understanding ...
math is fun's user avatar
5 votes
1 answer
811 views

A consequence of Firoozbakht's conjecture?

This is a question out of curiosity, while looking at the Firoozbakht's conjecture. It might not be research related, but as usual, I am not really sure if a question ever is research related or not, ...
mathoverflowUser's user avatar
5 votes
1 answer
737 views

Smallest prime factor of numbers

The literature refers to smooth integers as \begin{equation}\Psi(x,y):=\#\{n\le x:P_1(n)\le y\},\end{equation} where $P_1(n)$ is the largest prime factor of $n$. There are lots of results studying $\...
user avatar
5 votes
3 answers
809 views

Positive proportion of logarithmic gaps between consecutive primes

For $x, \lambda > 0$, define $$S_\lambda(x) := \#\{p_{n+1} \leq x : p_{n+1} - p_n \geq \lambda \log x\} ,$$ where $p_n$ is the $n$th prime number. It is known [1] that an uniform version of the ...
Kello's user avatar
  • 113
5 votes
1 answer
611 views

Why does this convolution of the prime counting function $\pi$ look like a parabola?

In this previous question it is shown that the convolution of the prime counting function $\pi$ with itself, is related to the Goldbach conjecture: $$\pi^*(n):=\sum_{k=0}^n \pi(k) \pi(n-k)$$ The ...
mathoverflowUser's user avatar
5 votes
1 answer
458 views

Moments of merit

The merit of a prime gap equals $(p_{n+1}-p_n)/\ln p_n$. One can interrogate the statistics of merit by first restricting $n<M$ for some $M$, and then letting $M$ approach $\infty$. The very ...
David Feldman's user avatar
5 votes
1 answer
436 views

Even sharper upper bound for prime product?

In Dusart papers he proves that $\prod \limits_{p \leq x} \frac{p_i}{p_i-1} \leq e^\gamma \ln (x) \left(1+\frac{0.2}{\ln ^2 (x)} \right)$ for large numbers. What I am asking is could we make the ...
user avatar
5 votes
2 answers
314 views

Congruences for the non-divisors of Euler's $\phi(n)$

If $n$ is composite, then $\phi(n) < n-1$: hence, there is at least one number $d$ which does not divide $\phi(n)$ but divides$(n-1)$. We shall call $d$ the totient divisor of $n$. The purist will ...
Nilotpal Kanti Sinha's user avatar

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