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Wieferich primes and identities for the Euler quotients of $2^n+1$ and $\frac{2^n+1}{3}$

Let $n>1$ be odd integer. Define the Euler quotient $a(n)=\frac{2^{\varphi(n)}-1 \bmod n^2}{n}$. Number $n$ with $a(n)=0$ is Wieferich number and if it is prime it is Wieferich prime. It is open ...
joro's user avatar
  • 25.4k
6 votes
1 answer
2k views

Difficulty with "A new elementary proof of the Prime Number Theorem" by Richter

I'm studying Richter's "A new elementary proof of the Prime Number Theorem" paper, and I'm finding some problems understanding some parts of it. For example, I don't see how to get, in Lemma ...
rr_math's user avatar
  • 63
1 vote
0 answers
100 views

Curious congruences modulo $4$ involving primes

We define $$S(n)=\sum_{a=2+(n\pmod 2)}^{n-2} \sharp(\{j,1\leq j<n \pmod{a},(a,j)=1\})\ .$$ (Searching the OEIS yielded no results.) For $n>2$ we have the following experimental observations (...
Roland Bacher's user avatar
-3 votes
0 answers
70 views

Is the upper bound on $H_{1}$ a decreasing function of the proportion of critical zeros of Zeta?

This question stems from https://arxiv.org/abs/2411.19762 and the numerical observation that the best unconditional upper bound for $H_{1}:=\lim\inf_{n\to\infty}p_{n+1}-p_{n}$, namely $H_{1}^{\flat}=...
Sylvain JULIEN's user avatar
17 votes
2 answers
2k views

Polynomials for natural numbers and irreducible polynomials for prime numbers?

Let $p$ be a prime and $n$ be a natural number. Define inductively for prime numbers: $f_1(x) := 1$, $f_2(x):=x$, $f_p(x) := 1+\prod_{q\mid p-1} f_q(x)^{v_q(p-1)}$. Is $f_p(x)$ always irreducible for ...
mathoverflowUser's user avatar
1 vote
0 answers
116 views

Can all congruences for a third-order recurrence relation hold for some composite $n$?

Let $p$ be a prime with $p \gt 3$. Consider the polynomial $f = x^3 - 3x -1$. Suppose $f$ is irreducible over $\mathbb{F}_{p}$. Let $E$ be the splitting field of $f$ over $\mathbb{F}_{p}$, and let $\...
David Bernier's user avatar
1 vote
0 answers
77 views

Conjecture about Euler quotients related to non-Wieferich numbers $W(n)=\frac{2^n+1}{3}$

For odd natural $n$ define the Euler quotient: $$ a(n)=\frac{(2^{\phi(n)}-1) \bmod n^2}{n}=\frac{2^{\phi(n)}-1}{n} \bmod n$$ $a(n)=0$ is $n$ being Wieferich number (not necessarily prime). For odd $n$,...
joro's user avatar
  • 25.4k
3 votes
1 answer
596 views

Primes which are safe and Sophie Germain

If $p$ is a Sophie Germain prime then $2p+1$ is safe prime. If $2p+1$ is safe prime then $p$ is Sophie Germain prime. What is their conjectured distribution of primes $p$ which are both Sophie ...
Turbo's user avatar
  • 13.9k
0 votes
0 answers
78 views

Factoring totient of a prime

Is it any easy to factor $p-1$ when $p$ is a prime compared to general factorization problem? What about when $2p+1$ is also a prime?
Turbo's user avatar
  • 13.9k
3 votes
0 answers
192 views

What smoothing to use for PNT-like results?

Consider a Dirichlet series $\sum_n a_n n^{-s}$ with desirable analytic properties (e.g., analytic extension to $\Re s>0$); one example would be $a_n=\mu(n)$. Say we want to estimate $\sum_{n\leq x}...
H A Helfgott's user avatar
  • 20.2k
3 votes
1 answer
157 views

Three congruences for a Perrin-like sequence and pseudoprimes

Let $ V(n) $ be defined by the recurrence relation: $$ V(n) = 3\,V(n-2) + V(n-3) $$ with the initial conditions: $$ V(0) = 3, \quad V(1) = 0, \quad \text{and} \quad V(2) = 6. $$ If $ n $ is an odd ...
David Bernier's user avatar
1 vote
1 answer
171 views

Are all integers up to $x$ but possibly $O_{\varepsilon}(x^{\varepsilon})$ the sum of $a$ squares and $b$ primes with $a+b\leq 3$?

This question is related to https://math.stackexchange.com/questions/3710032/conjecture-all-but-21-non-square-integers-are-the-sum-of-a-square-and-a-prime. We know since Lagrange that every natural ...
Sylvain JULIEN's user avatar
2 votes
0 answers
110 views
+50

How to apply Pohlig Hellman using a very limited set of auxiliary inputs in that case?

So I was reading about Talotti, Paier, and Miculan - ECC’s Achilles’ Heel: Unveiling Weak Keys in Standardized Curves. The underlying idea is to lift the discrete logarithm problem to $\mathrm{prime}−...
user2284570's user avatar
1 vote
1 answer
199 views

Weights in the proof of Chen's theorem in Nathanson's "Additive Number Theory The Classical Bases"

I was reading Professor Nathanson's graduate texts in mathematics 164: "Additive Number Theory The Classical Bases" (http://www.alefenu.com/libri/nathansonbases.pdf), and I was wondering if ...
Rick's user avatar
  • 13
1 vote
0 answers
89 views

Test for odd prime triples in a $2p-1$ progression

Let $a(n)$ be A057326 (i.e., first member of a prime triple in a $2p-1$ progression). Let $b(n) = B$ after $n-1$ iterations where we start with $A=n, B=1$ and for $i$ from $1$ to $n-1$ simultaneously ...
Notamathematician's user avatar
0 votes
0 answers
241 views

Conjecture about some recurrent primes

I want to know if there are conjectures similar to this one, I know there is the Bell primes conjecture or Gardner conjecture (mentioned in this page https://en.wikipedia.org/wiki/Bell_number), but ...
Abdelhay Benmoussa's user avatar
4 votes
0 answers
266 views

How dense are quotients of smooth numbers?

As usual, call a positive integer $y$-smooth if it has no prime factors greater than $y$. Write $S(x,y)$ for the set of $y$-smooth integers $\leq x$. Write $R(x,y)$ for the set of quotients $\{a/b: a,...
H A Helfgott's user avatar
  • 20.2k
1 vote
0 answers
127 views

Some property of the greatest prime factor

Let $n$ be a positive integer $\geq 2$ et denote by $ P^{+}(n)$ the greatest prime factor of $n$ my question is as follows: If $a$ and $b$ are two numbers, is there any method to express or to bound $...
Khadija Mbarki's user avatar
1 vote
1 answer
373 views

$\{ x/p\} $ on average

This is a vague question: Lemma 2.2 of Friedlander and Lagarias' "On the distribution in short intervals of integers having no large prime factor" says that $$\sum _{p\leq w}\left (\{ x/p\} -...
tomos's user avatar
  • 1,381
0 votes
0 answers
374 views

Is the Conjecture of Representing Integers as Differences of Semiprimes and Primes Extendable to Products of Distinct Primes?

Conjecture: Let $k$ and $l$ be fixed distinct positive integers ($k≠l$). Then, for every positive integer $n$, there exist prime numbers $p_1,p_2,…,p_k∈\mathbb{P}$ and $q_1,q_2,…,q_l∈\mathbb{P}$ such ...
Akira Sukigi's user avatar
2 votes
1 answer
221 views

A question on signed Stirling numbers of the first kind

Let $(x)_0=1$ and $(x)_n=x(x-1)\cdots(x-n+1)$ for $n=1,2,3,\ldots$. The signed Stirling numbers of the first kind, $s(n,k)$ with $n\ge k\ge0$, are defined by $$(x)_n=\sum_{k=0}^ns(n,k)x^k.$$ Question. ...
Zhi-Wei Sun's user avatar
  • 15.6k
1 vote
0 answers
170 views

Character sums over prime

Let $\chi$ be a quadratic character mod $q$. I am interested in finding the best result for how large $N$ should be such that it is guaranteed that $$\sum_{p=1}^{N} \chi(p) \log p= o(N).$$ I am aware ...
Farzad Aryan's user avatar
-3 votes
1 answer
201 views

Formula for gaps between primes [closed]

The twin prime conjecture refers to: $$ \liminf_{n\to \infty}\; p_{n+1} - p_{n} = 2. $$ By reasoning I arrive at the following simple formula for gaps between primes: \begin{align} p_{...
Wayne's user avatar
  • 13
0 votes
0 answers
169 views

On a property of prime numbers

Let $p_i$ be the $i^{\rm th}$ prime number (i.e. $p_1=2,\ p_2=3,\ p_3=5,\cdots$) What is the function of number of combinations of $c_1,\cdots,c_n$ in terms of $n$ such that, $$\sum_{i=1}^{n}c_ip_i\ =\...
yash vinayvanshi's user avatar
4 votes
1 answer
240 views

Do there exist prime numbers of the form $n \cdot 2^n + 1$, when $n \in \mathbb{N}$ and $n > 1$?

Recently, I was studying prime sequences of the form $k \cdot 2^n + 1$, and I noticed that primes of the form $n \cdot 2^n + 1$ almost do not exist, except for the $n = 1$ case. Are there other prime ...
Arsen Vardanyan's user avatar
0 votes
0 answers
102 views

Formalizing the "pseudorandomness" of primes

Many conjectures about primes seem to revolve around the idea of "primes are random". So I thought about how this "randomness" may be formally defined, and came up with the ...
XM73's user avatar
  • 1
2 votes
0 answers
76 views

upper and lower bounds on rowlands sequence

rowlands sequence is defined as follows \begin{equation} a_{n}=a_{n-1} + b_{n} \end{equation} where $b_{n} = gcd(a_{n-1}, n)$ for $n>h$ it originates from E. Rowlands 2008 paper "A Natural ...
Antisocialfreal's user avatar
3 votes
1 answer
216 views

Are there any positive integers $n$, $k$ such that $n > 2, k > 6$, and all prime factors of $n^k - 1$ are less than $n$?

I noticed that the prime factorization of $68^6 - 1$ is $3^2 \cdot 7^2 \cdot 13 \cdot 19^2 \cdot 23 \cdot 31 \cdot 67$, which makes all of its prime factors less than 68. This made me wonder the ...
William Hu's user avatar
1 vote
0 answers
60 views

On the parity of $(2^{\varphi(n)}-1) \bmod{n^2}$

For odd integer $n$ define the function $$ J(n)=(2^{\varphi(n)}-1) \bmod{n^2}$$ $J(n)$ is integer in $[0,n^2-1]$ and it is divisible by $n$. Integer $n$ is Wieferich number iff $J(n)=0$ and if $n$ is ...
joro's user avatar
  • 25.4k
5 votes
0 answers
261 views

Primes generated by cyclotomic polynomials

Let $p$ be an odd prime, and let $f=\Phi_p$ be the $p$-th cyclotomic polynomial. Denote by $S_p$ the set of primes $q$ such that there exists a sequence of primes $p_1,\dots, p_g$ such that $p_1=f(1)=...
Maurizio Moreschi's user avatar
4 votes
1 answer
409 views

On the parity of the sum $\sum_{1\le j<k\le p-1\atop p\nmid aj^2+bjk+ck^2}(aj^2+bjk+ck^2)$

QUESTION. Let $p$ be an odd prime and let $a,b,c\in\mathbb Z$. How to determine the parity of the sum $$S_p(a,b,c)=\sum_{1\le j<k\le p-1\atop p\nmid aj^2+bjk+ck^2}(aj^2+bjk+ck^2)$$ in terms of $a,b,...
Zhi-Wei Sun's user avatar
  • 15.6k
7 votes
1 answer
276 views

From $\Lambda_k$ and $\Lambda$ to $\mu$ (or $\lambda$)

Let $\{a_n\}_{n=1}^\infty$, $a_n \in \mathbb{C}$, $|a_n|\leq 1$. Let $\Lambda_k = \mu \ast \log^k$; in particular, $\Lambda_1$ equals the von Mangoldt function $\Lambda$. Suppose that we have ...
H A Helfgott's user avatar
  • 20.2k
5 votes
1 answer
172 views

On vanishing of $p$-adic logarithms

Might be related to Wieferich primes. Let $p$ be odd prime and define the Fermat quotient $$F(n)=\frac{(2^{n-1} -1)}{n} \mod n=\frac{(2^{n-1} \bmod n^2 )-1}{n}$$ For integer $b$ let $L_p(b)$ be the $p$...
joro's user avatar
  • 25.4k
2 votes
0 answers
108 views

Largest prime determinant of a binary matrix

Given an integer $n$, I want to prove the existence of an $n\times n$ binary matrix (with 0,1 entries), whose determinant is a prime number. What is a lower bound on the largest determinant that I ...
Erel Segal-Halevi's user avatar
0 votes
0 answers
62 views

On base $b$ digits of $n\#$ (primorial)

Related to normal numbers. Let $n\#$ denote the primorial, the product of the first $n$ primes. Q1 For all bases $b>1$, do the base $b$ digits of $n\#$ occur with equal asymptotic frequency $\...
joro's user avatar
  • 25.4k
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
4 votes
1 answer
403 views

Möbius square root function: existence of multiplicative and bounded function

With $\mu$ being the Möbius function, there exist infinite possibilities of square roots. For example, for each $n$ such that $\mu(n)\neq 0$ there is a choice: if $\mu(n)=-1$, we can choose to define $...
Virgile Dine's user avatar
9 votes
2 answers
794 views

Why do these finite group Dedekind matrices seem to have integer spectrum when specialized to the order of group elements?

Let $p$ be a prime and let $f_p$ be the permutation on the set $\{1,2,\cdots,p-1\}$ which is given by taking inverses in $\mathbb{Z}/(p)$: $$x \bmod(p) \mapsto \frac{1}{x} \bmod (p)$$ So for instance, ...
mathoverflowUser's user avatar
4 votes
2 answers
737 views

On finite products of $\frac{p+4}{p+2}$ with $p$ prime

Let us consider factorizations of rational numbers greater than one. For integers $a>b>0$, clearly $$\frac ab =\prod_{n=b}^{a-1}\frac{n+1}n.$$ In view of Question 476578 and Max Alekseyev's ...
Zhi-Wei Sun's user avatar
  • 15.6k
1 vote
0 answers
151 views

On lacunary series connected with prime number theory

Consider the following lacunary sum with parameter $x$: $$S(x)=\sum_{n=5}^{\infty}\sin^2\left(\frac{x\Gamma(n)}{n}\right).$$ As we can see for $x=\frac{\pi}{2}$ the sum becomes$$\sum_p\cos^2\left(\...
TPC's user avatar
  • 790
2 votes
1 answer
159 views

Primality of divisor sums

Let $k \geq 2$ be an integer. Put $[k] = \{1, \cdots, k\}$. Let $\mathcal{P} = \{p_1, \cdots, p_k\}$ be a set of $k$ primes. For every subset $S \subseteq [k]$ put $d_S = \prod_{j \in S} p_j$. The ...
Stanley Yao Xiao's user avatar
15 votes
4 answers
2k views

Square roots and prime numbers

Definitions: Here I present a novel conjecture using basic mathematical tools like the sum of the divisors of an integer $n$ called $\sigma(n)$, the sum of the squares of the positive divisors of n ...
Sulfura's user avatar
  • 127
1 vote
0 answers
78 views

Partial sums of Möbius function and Euler characteristic of a simplicial complex for closed sets of a topology on the prime powers?

In A cell complex in number theory by Anders Björner, 2011 a number theoretic cell complex is described which has the property that the Euler characteristic is related to the Mertens function: $$M(n) =...
mathoverflowUser's user avatar
4 votes
0 answers
145 views

Bounding an expression equivalent to Mertens function

Cross-posted from MathStackExchange, where the question is bountied but has not received any comment or answer) Some months ago, I derived the following formula for the Merten's function $M(n)$ using ...
Juan Moreno's user avatar
0 votes
0 answers
122 views

Explicit upper bounds on the number of primes up to the square of the $n^\text{th}$ prime number $p_n$

I'm looking for explicit upper bounds on the number of primes up to the square $m=p_n^2$ of the $n^\text{th}$ prime number. Such estimates can rely on the knowledge of the exact number of primes up to ...
Nautilus's user avatar
  • 727
8 votes
0 answers
150 views

Can P-recursive functions assume only prime values?

A function $f\colon \{0,1,\dots\}\to \mathbb{R}$ is P-recursive if it satisfies a recurrence $$ P_d(n)f(n+d)+P_{d-1}(n)f(n+d-1)+\cdots+P_0(n)f(n)=0,\ n\geq 0, $$ where each $P_i(n)\in \mathbb{R}[n]$ ...
Richard Stanley's user avatar
1 vote
1 answer
78 views

Minimum value of a function involving the divisor counting function

Fix any positive integer $n\in\mathbb{Z}^+,$ and consider the function $f_n : \mathbb{Z}^+\setminus\{n\}\to\mathbb{Z}^+$ given by $$f_n(t)=\sigma_0(n)+\sigma_0(t)-2\sigma_0(\gcd(n, t)),$$ where $\...
Bumblebee's user avatar
  • 1,093
3 votes
0 answers
153 views

On a theorem by Iwaniec about binary quadratic polynomials representing infinitely many primes

In Theorem 1.1 (i) of http://matwbn.icm.edu.pl/ksiazki/aa/aa24/aa2451.pdf, Iwaniec showed that a certain type of quadratic polynomial $P(x,y)$ represents infinitely many primes, where $(x,y) \in \...
Markiff's user avatar
  • 333
1 vote
0 answers
99 views

On the existence of a sequence of prime numbers satisfying a recursion relation

I am interested in the following question. I will be grateful for any reference, comment, or solution. Let $p_1\geq 5$ be a given prime number. Does there exist an infinite sequence of prime numbers $...
Janko Bracic's user avatar
8 votes
2 answers
393 views

Can exist a positive integer number $x$ such that $a_1=x$ and $a_n=2a_{n-1}+1$ are not prime for all $n \ge 1$?

Using my computer, I found that the most of positive integer number $x$ such that $a_1=x$ and $a_n=2a_{n-1}+1$ is prime number after a few iterations. But exist some positive integer numbers, my ...
Đào Thanh Oai's user avatar

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