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69 votes
4 answers
14k views

Is a "non-analytic" proof of Dirichlet's theorem on primes known or possible?

It is well-known that one can prove certain special cases of Dirichlet's theorem by exhibiting an integer polynomial $p(x)$ with the properties that the prime divisors of $\{ p(n) | n \in \mathbb{Z} \}...
2 votes
0 answers
125 views

Conditional stronger bounds on Linnik theorem with prime power modulus

This post is related to questions asked here and here. However, I include the relevant background on least prime in arithmetic progressions presented here for benefit of the reader. By Linnik's ...
5 votes
1 answer
392 views

Divergence of primes dividing polynomials

Let $Q : \mathbb{Z} \rightarrow \mathbb{Z}$ be a polynomial. Form the set $$M_{Q} := \{p:\text{ }p\text{ is prime, }\exists n_{p}\in \mathbb{Z}\text{ so that }p|Q(n_{p})\}$$ Is $$\sum_{s \in M_{Q}}\...
1 vote
0 answers
83 views

Prime powers gap of type $(a,b)$

For $n$ a given positive integer, say $r$ is a Galois radius of $n$ of type $(a,b)$, level $l=ab$ and rank $\rho=a+b$ if $n-r=p^a$ and $n+r=q^b$ with both $p$ and $q$ prime. Denote by $PPG_{a,b}(m)$ ...
2 votes
1 answer
159 views

Is the density of integers $n$ such that the finite sequence $(\omega(n-r)\omega(n+r))_{0\leq r\leq n-1}$ is surjective positive?

Let $\omega(m)$ be the number of prime factors of $m$ regardless of multiplicity. I'm interested in the behavior of the finite sequence $(\omega(n-r)\omega(n+r))_{0\leq r\leq n-1}$ for a given integer ...
2 votes
1 answer
545 views

Is there a Cramer's conjecture for Sophie Germain primes?

A prime $q$ such that $2q+1$ is also a prime is a Sophie Germain prime. Cramer's conjecture tells gap between consecutive primes is bound by $O(\log^2p)$. Is there a similar conjecture for Sophie ...
4 votes
1 answer
531 views

Do prime gaps that are a power of "h" have the same density?

Send me back to Mathematics Stack Exchange if this question is not research level. At Terence Tao's blog post there is the expression: $$\sum\limits_{n \leq X} \Lambda(n)\Lambda(n+h) \ \ \ \ \ \ \ \ \ ...
9 votes
1 answer
400 views

The difference between consecutive primes in arithmetic progressions

Let $\pi(x)=\sum_{p\leq x}$ denote the prime counting function. A well known result of Baker, Harman, and Pintz on prime gaps states that for $x\geq y\geq x^{0.525}$ we have that $$\pi(x+y)-\pi(x)\gg \...
3 votes
0 answers
158 views

What can be said about the primality of Zsigmondy numbers?

I am cross-posting this from math.stackexchange, as it has received upvotes but no comments/answers after a couple months. Let $\mathcal{Z}(n,a,b)=\frac{\Phi_n(a,b)}{\gcd (\Phi_n(a,b),n)}$ be the $n$-...
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 $C$ ...
3 votes
0 answers
151 views

On an inequality for the arithmetic function counting the number of primes $\lfloor n^c\rfloor$ in the spirit of Ramanujan's prime counting inequality

In page 3 of [1] (please see if you need it the book by Berndt) Axler refers an inequality that involves the prime-counting function $\pi(x)$ and that was deduced by Ramanujan. I'm curious to know if ...
9 votes
2 answers
699 views

Is there a connection of prime numbers and extreme value theory?

As most others are, so am I fascinated by primes. By the theorem of Euclid and the sieve of Eratosthenes the $ k \ge 2$ - th prime is given by: $$ p_k = \min_{x>1,\gcd(x,p_1 \cdots p_{k-1})=1} x ...
0 votes
0 answers
82 views

Inequalities $\pi(x^a+y^b)^\alpha\leq \pi(x^c)^\beta+\pi(y^d)^\gamma$ involving the prime-counting function, where the constants are very close to $1$

Let $\pi(x)$ be the prime-counting function, I'm curious about if a suitable variant of the second Hardy–Littlewood conjecture (this corresponding Wikipedia) $$\pi(x^a+y^b)^\alpha\leq \pi(x^c)^\beta+\...
3 votes
0 answers
429 views

Proof of an explicit formula for $\pi_0(x)$

Let $\pi(x)$ denote the prime counting function and $$\pi_0(x) = \lim_{\epsilon \to 0} \frac{\pi(x+\epsilon)+\pi(x-\epsilon)}{2}.$$ I've seen noted in a few references the explicit formula $$\pi_0(x) =...
13 votes
2 answers
1k views

Existence of relative Dirichlet density of primes starting with 1

This question is a duplicate of an existing MO question, but that other MO question has an accepted answer that does not actually answer the question, and I'm not sure how to fix that other than by re-...
8 votes
2 answers
814 views

Estimates about prime numbers: a lemma in Bourgain's article

For $n\in \mathbb{N}$ with prime decomposition $n=p_1^{r_1}\cdots p_k^{r_k},p_i\neq p_j$, let $A=\{p_1,\cdots,p_k\}$; then the following holds: \begin{equation} |\{q\in \mathbb{N},q<Q: \text{all ...
1 vote
0 answers
240 views

Liu's new sieve weight

Does Liu's sieve weight (in his arXiv paper "On the gap between primes") $$sieve(n)=(\sum_{\substack{d_i\mid (n-h_i),i=1,\cdots,k\\ (d_1,\cdots,d_k)\in\mathcal{D}}}\lambda_{d_1,\cdots,d_k} ...
1 vote
0 answers
750 views

Can the prime gap record of Liu be improved further?

Let $d$ be the least positive integer such that there are infinitely many distinct prime pairs $\{p,q\}$ with $|q-p|\le d$. The twin prime conjecture is equivalent to $d=2$. In 2013 Yitang Zhang ...
2 votes
0 answers
144 views

A conjecture about prime test

Conjecture If $\varphi(m)<\varphi(n)$ for all $m<n$,then $n$ is a prime number. I tried to find a counterexample when $n=pq$ ($p,q$ are prime), then we have to find a prime between $(p-1)(q-1)$ ...
4 votes
1 answer
219 views

Numbers $n$ whose representation as the product of two divisors require more digits than that of $n$

Note: Posting in MO since it was unanswered in MSE Let $f(x)$ be the number of digits in the decimal representation of $x$ e.g. $, f(0) = 1, f(1729) = 4$. If $n = ab$ then we can show that $f(ab) > ...
9 votes
3 answers
584 views

Why is there an unexpected increase in the density of certain types of Goldbach primes?

Note: Posted in MO since it was unanswered in MSE. I was checking how quickly we can verify Goldbach's conjecture for a given even number $n$ and it was clear that searching backward starting from the ...
4 votes
0 answers
210 views

No perfect patterns in the primes

The primes are equidistributed in the residue classes $1(\!\!\!\mod{4})$ and $3(\!\!\!\mod 4)$. We also know (for example, by Rubinstein-Sarnak) that the patterns cannot be eventually alternating, i.e....
9 votes
2 answers
547 views

Primes between $x$ and $x+x^\theta$

Iwaniec [1] proved that $$ \pi(x+x^\theta)-\pi(x) < \frac{(2+\varepsilon)x^\theta}{\eta(\theta)\log x},\ x>x_0(\varepsilon,\theta). $$ with $$ \eta(\theta)=\frac{15\theta-2}{9}. $$ (Actually, he ...
4 votes
1 answer
235 views

Relation between $\pi$, area and the sides of Pythagorean triangles whose hypotenuse is a prime number

Consider all Pythagorean triangles $a^2 + b^2 = p^2$ in which the hypotenuse $p$ is a prime number. Let $h(x) = \sum_{p \le x}p^2$, $a(x) = \sum_{p \le x}ab$ and $r(x) = \sum_{p \le x}(a+b)^2$. Is it ...
-3 votes
1 answer
271 views

Is this Goldbach conjecture related quantity equal to the number of Goldbach decompositions up to a bounded quantity?

This question is a follow-up to About Goldbach's conjecture and as such deals with the notion of primality radius of a composite integer $n$, that is, a positive integer $r$ such that both $n-r$ ...
0 votes
0 answers
177 views

Is there a link between Elliott-Halberstam and weak Hardy-Littlewood-Goldbach conjectures?

Let $\theta$ be such that $EH(\theta)$ holds, where $EH$ stands for Elliott-Halberstam. Can one get an explicit lower bound $\delta_{\theta}$ for the quantity $\delta$ appearing in the weak Hardy-...
42 votes
2 answers
9k views

Is Li(x) the best possible approximation to the prime-counting function?

The Prime Number Theorem says that $\lim_{n \to \infty} \frac{\pi(n)}{\mathrm{Li}(n)} = 1$, where $\mathrm{Li}(x)$ is the Logarithm integral function $\mathrm{Li}(x) = \int_2^x \frac{1}{\log(x)}dx$. ...
1 vote
0 answers
84 views

How common are semiprimes with equally bitsized factors among semiprimes with equal bitsize?

I am curious about the following after having looked at the paper "Almost primes in almost all short intervals", theorem 3 says: Almost all intervals $[x, x + \log^{3.51}{(x)}]$ with $x ≤ X$...
34 votes
7 answers
8k views

Explicit formula for Riemann zeros counting function

I've often seen it stated (in vague terms) that there's a Fourier duality between the set of prime numbers and the set of nontrivial Riemann zeta zeros. Because there are various explicit formulae ...
1 vote
1 answer
306 views

Expected number of primes of particular size and from a linear form

Given two distinct primes $P_1$ and $P_2$ picked randomly and uniformly in the interval $[T^2,2T^2]$ consider the set $\chi(P_1,P_2)$ of numbers of form $$xP_1-yP_2$$ where $x,y$ are in $[0,T^{1+\...
5 votes
1 answer
214 views

Remainder terms of congruence sums in sets of positive density

Let $\mathcal{A} \subset \mathbb{N}$ be an infinite sequence with positive density, in the sense that $$ \tag{1} \lim_{x\to\infty} \frac{|\mathcal{A} \cap x|}{x} = c > 0, $$ and define the ...
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(\...
10 votes
0 answers
350 views

Are there are any attempts utilising sieve theory to attack the general $a p \pm 1$ problem?

It is currently an open question if there are infinitely many primes $p$ such that $2p + 1$ is prime (Sophie Germain primes) or that at least one of $24p \pm 1$ is prime. Could Zhang's method, or the ...
3 votes
0 answers
292 views

A prime generating algorithm

I posted this question in MSE around a month ago, but didn't receive any suitable answers. So, I decided to give it a try here as well- I was trying to explain the famous proof of infinitude of primes ...
1 vote
1 answer
124 views

why is $R := \mathbb{Z}p +XF[[X]]$ an almost valuation domain?

Recall that an integral domain $R$ with quotient field $K$ is an almost valuation domain if for every $0 \not= x \in K$, there is a positive integer $n$ (depending on $x$) such that $x^n \in R$ or $x^{...
4 votes
0 answers
922 views

Guessing of $n$th prime from "super- regularized" product of primes

( I've been thinking about asking this for a long time . Though this is not rigorous; It can be thought of as heuristic or extraction of information from different viewpoint.) We know "super-...
0 votes
1 answer
97 views

$l$-th power radioprimal conjecture

I would like to know if some widely believed conjecture, be it GRH, Hardy-Littlewood conjecture, or any other would imply the following statement for some $l>1$: $l$-th power radioprimal growth ...
10 votes
2 answers
282 views

Non-trivial upper bound for a sum related to $p^{-1}z \pmod q$ and $q^{-1}z \pmod p$

Let $p, q$ be two distinct prime number. I'm trying to provide a non-trivial upper bound for the sum $$S(p, q) = \sum_{1 \leq x < p} \sum_{1 \leq y < q} \frac{1}{\|x / p\| \, \|y / q\| \, \|x/p +...
21 votes
1 answer
1k views

Primes that are sums of two squares with constraints on the squares

It is well known that there are infinitely many primes of the form $a^2+b^2$ (namely all primes congruent to $1$ modulo $4$). On the other hand, Euler raised the problem as to whether there are ...
8 votes
2 answers
1k views

Prime plus square equals prime

Furstenberg–Sárközy's theorem states that if a set of positive integers has positive upper density, then there exists (infinitely many) pair of elements of the set, whose difference is a perfect ...
5 votes
0 answers
349 views

Smallest prime $p$ such that $2\mid\operatorname{ord}_p(q)$, the multiplicative order of $q$ modulo $p$

$\DeclareMathOperator\ord{ord}$Let $q$ be prime. I want to upper bound the smallest odd prime $p$ such that $2\mid\ord_p(q)$ (where $\ord_p(q)$ is the multiplicative order of $q$ modulo $p$). Using ...
13 votes
2 answers
1k views

What is known about the prime number theorem for Beurling generalised primes

Background: Beurling's systems of numbers Beurling considered a sequence of reals $1<x_1<x_2<\cdots <$ as "primes" and then the ordered sequence of all products of these "...
16 votes
1 answer
4k views

Order of magnitude of $\sum \frac{1}{\log{p}}$

Question: What is the order of magnitude of the following sum? $$ \sum_{\substack{p<n\\\text{$p$ prime}}} \frac{1}{\log{p}} $$ Additional information: Since $$ \sum_{\substack{p<n\\\text{...
3 votes
0 answers
232 views

Numbers made up of primes from a given set

Take a set $\mathcal P$ of primes and denote by $\langle \mathcal P\rangle $ the set of all natural numbers composed of primes from $\mathcal P$. If \[ \sum _{p\in \mathcal P}\frac {1}{p}\] converges ...
3 votes
0 answers
117 views

On the Carmichael Lambda function

Let Carmichael function be denoted by $\lambda(n)$. Consider the set $I_m=\{n:\lambda(n)=m\}$. What is known about the cardinality of $I_m$? Let $P_m=\{p\in Primes: p|\ell \mbox{ for some }\ell\in ...
0 votes
0 answers
102 views

On simple examples of unimodularity

$w=z=x+ 1 =y−1$ provides $wz−xy=w^2−(w−1)(w+ 1) = 1$. Hence if $x,y$ are odd then $w,z$ are even and all four integers are close. Is there elementary example where only $w$ is even and all four ...
4 votes
1 answer
400 views

Bounding integrals involving $\operatorname{li}(x)-\pi(x)$

Let $x >0$. How can one find good $O$ bounds on the integrals $$\int_0^x\frac{\operatorname{li}(t)-\pi(t)}{t}dt$$ and $$\int_x^\infty\frac{\operatorname{li}(t)-\pi(t)}{t^2}dt$$ where $\pi(x)$ is ...
2 votes
1 answer
461 views

How essential is the vanishing of the Dirichlet $L$-functions to Dirichlet's theorem on primes in arithmetic progressions?

I seem to recall that the prime number theorem (PNT) is equivalent to the fact that the Riemann zeta function $\zeta(s)$ is non-zero on all of $\text{Re}(s) = 1$ (see https://math.stackexchange.com/...
5 votes
0 answers
326 views

Counting primes, twin primes, cousin primes: unusual approach, connection to some conjectures

I am investigating the following sieve-like algorithm. Let $S_N=\{1,\dots,N\}$. For all primes $p$ with $p_0\leq p \leq M$, we remove from $S_N$ the following elements: all numbers $n\in S_N$ such ...
2 votes
0 answers
243 views

Primes in arithmetic progression

We call a prime $p$ "good" if there is $0<k<\log p$ with $2kp+1$ prime. What is the asymptotic density of good primes?

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