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Questions where prime numbers play a key-role, such as: questions on the distribution of prime numbers (twin primes, gaps between primes, Hardy–Littlewood conjectures, etc); questions on prime numbers with special properties (Wieferich prime, Wolstenholme prime, etc.). This tag is often used as a specialized tag in combination with the top-level tag nt.number-theory and (if applicable) analytic-number-theory.

2 votes
Accepted

Asymptotics for a peculiar kind of squarefree numbers

Please ignore the previous version of this answer. Motivated by Lucia's comment, we use smooth numbers to show that the number in question is $o(x)$. First note that for $100\%$ of all integers one h …
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4 votes
0 answers
209 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 …
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3 votes
0 answers
333 views

Conditional proof of ternary Goldbach

This is a reference request. I know that Hardy and Littlewood gave a proof of the ternary Goldbach for sufficiently large odd integers under the assumption of GRH. Is there a modern account of th …
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3 votes

A question on the prime divisors of p-1

A few more ideas: using the Chebyshev upper bound, by partial summation we have $\sum_{p>y}p^{-2}=O(\frac{1}{y \log y})$ and therefore we see that $s(n)=\sum_{p \leq \frac{n}{\log n}}\frac{(p-1,n)}{ …
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4 votes
Accepted

Tail of singular series of Goldbach problem

Here is an unconditional error: Restricting to summation over $q$ with $gcd(q,N)=n$ and using the formula for Ramanujan sums implies that the quantity you stated equals $$\sum_{n|N}\frac{\mu^2(n)}{\p …
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2 votes
0 answers
158 views

Quadratic patterns in summands of Goldbach's conjecture

Let $n $ be even and define $$ Q(n)=\sum_{\substack{ p,q \ \textrm{ primes} \\p+q=n }}\left(\frac{p}{q} \right),$$ where $\left(\frac{p}{q} \right)$ is the quadratic Legendre symbol. Has this sum been …
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18 votes
3 answers
2k views

A question on the prime divisors of p-1

For each positive integer n we may define the convergent sum $$ s(n)=\sum_{p}\frac{(n,p-1)}{p^2} $$ where the summation is over primes p and $(a,b)$ denotes the greatest common divisor of a,b. It is …
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2 votes

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

One can prove that in fact the function mpe has bounded average which clearly improves $\log \log$. If a positive integer n has $mpe(n)=m$ then there exists a prime power p^m that divides n hence the …
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2 votes
1 answer
137 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 …
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  • 3,062
6 votes
0 answers
504 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 inte …
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  • 3,062
3 votes
1 answer
353 views

Squarefree values of polynomials at prime arguments

This is a reference request. Assume that $f_1,\ldots,f_r \in \mathbb{Z}[t]$ are non-zero linear polynomial. Letting $\mu$ be the M\"{o}bius function, is there any work on $$ \sum_{p\leq x} \prod_{i …
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  • 3,062
3 votes
2 answers
440 views

Least number coprime to a given integer

For a positive integer $n$ let $$f(n):=\min\{m\in \mathbb N: m>1, \gcd(m,n)=1\} .$$ Equivalently, $f(n) $ is the smallest prime not dividing $n$. Is there any upper bound literature for this? It is no …
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4 votes

Divisor sums over values of binary forms of primes

An answer regarding the use of large sieve suggested by Lucia (too long for a comment). I guess her/his thought was along the following lines: The divisors $d$ of $p^2+q^2$ are of order $x^2$ and …
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3 votes
0 answers
187 views

Riemann's explicit formula for square-free numbers

We know that for $x$ being a half-integer $$\sum_{n\leq x}\Lambda(n)=x-\sum_{\rho}\frac{x^\rho}{\rho}+O(1).$$ Is there a similar formula for $\sum_{n\leq x}\mu(n)^2$ in the literature? The underlying …
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5 votes
Accepted

Explicit bounds on number of squarefree numbers coprime to a certain number

I am assuming that explicit refers to the error term? In this case you can write $$Q_A(x)=\sum_{d\mid A}\mu(d)\sum_{k\leq \sqrt x \atop \gcd(A,k)=1}\mu(k)\left[\frac{x}{dk^2}\right],$$ where $[t]$ den …
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