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$ f(s) = 1 + \sum_{n=2}^{\infty} \frac{n^{-s}}{p_n}= 0$?

Let $p_n$ be the $n$ th prime number. Let $f(s)$ be a Dirichlet series defined on the complex plane as : $$f(s) = 1 + \sum_{n=2}^{\infty} \frac{n^{-s}}{p_n}= 1 + \frac{2^{-s}}{2}+ \frac{3^{-s}}{3} + \...
mick's user avatar
  • 16.4k
2 votes
1 answer
83 views

How to compute constants in asymptotic density of numbers divisible by subset of primes

I'm interested in the asymptotic density of the set $S$ of natural numbers divisible only by primes $p \equiv 1 \bmod 4$ (and similar subsets of $\mathbb{N}$). I'm aware of results which show that the ...
h4tter's user avatar
  • 499
0 votes
0 answers
67 views

Question on convergence of product and Dirichlet series representations of a function

Consider the following two representations of $f(s)$ $$f(s)= \underset{K\to\infty}{\text{lim}}\left(\prod\limits_{k=1}^K \left(1-\frac{2}{\left.p_k\right.^s}\right)\right)\tag{1}$$ $$f(s)=\underset{N\...
Steven Clark's user avatar
  • 7,631
1 vote
1 answer
474 views

For which $s$ does $\sum 1/p^s$ converge?

A well-known result is that $\sum 1/n^s$ converges for $\operatorname{Re}(s)>1$. Question: For which $s$ does $\sum 1/p^s$ converge, where $p$ is over all primes? Notes: Intuitively there are ...
Penelope's user avatar
  • 3,325
2 votes
1 answer
111 views

Product over the primes with relation to the Dirichlet series

What is the value of $\displaystyle \prod_p\left(1+\frac{p^s}{(p^s-1)^2}\right)$ I got this product by defining a function $a(n)$ such that $a(n)=a(p_1^{a_1}p_2^{a_2}p_3^{a_3}...p_n^{a_n})=a_1a_2a_3......
Lettever's user avatar
3 votes
1 answer
169 views

How to calculate $ \sum_{n=1}^\infty\frac{3^{\omega(n)}\Omega(n)}{n^s} $?

For $s\in\mathbb C$ with say $\Re s>1$, how to write $$ \sum_{n=1}^\infty\frac{3^{\omega(n)}\Omega(n)}{n^s} $$ in terms of the Riemann Zeta function (where $\omega$ is the number of prime factors ...
Redundant Aunt's user avatar
3 votes
0 answers
143 views

Questions about the Dirichlet series $K(s)=\sum\limits_{p^k} p^{\,-k\,s}$

This question is related to Riemann's prime-power counting function $J(x)$, the fundamental prime-counting function $\pi(x)$, and the simple prime-power counting function $k(x)$ defined below where $p\...
Steven Clark's user avatar
  • 7,631
2 votes
1 answer
105 views

Dirichlet sum involving coprimes to p#

This exercise seemed straightforward but I have not managed to do the following proof. Let $p\#$ be the product of primes not exceeding p. Let $c(n)$ be the nth coprime to $p\#$ (mod 2,3,...,p). Let $...
daniel's user avatar
  • 10.3k
6 votes
0 answers
202 views

Questions related to the Dirichlet series for $\frac{\zeta'(s)}{\zeta(s)^2}$

This question is related to the following two functions evaluated with the coefficient function $a(n)=\mu(n)\log(n)$. (1) $\quad f(x)=\sum\limits_{n=1}^x a(n)$ (2) $\quad\frac{\zeta'(s)}{\zeta(s)^2}=...
Steven Clark's user avatar
  • 7,631
2 votes
1 answer
262 views

Questions related to Moebius Transform of Characteristic Function of the Primes

Consider the function $f(x)$ defined in (2) below related to the fundamental prime counting function $\pi(x)$ defined in (1) below. Note $b(n)$ is the Möbius transform of $a(n)$. (1) $\quad \pi(x)=\...
Steven Clark's user avatar
  • 7,631
2 votes
0 answers
92 views

What are the Dirichlet transforms of $\Lambda(n+1)$ and $\frac{\Lambda(n+1)}{\log(n+1)}$?

This question assumes the following definitions. (1) $\quad\psi(x)=\sum\limits_{n\le x}\Lambda(n)\qquad\text{(second Chebyshev function)}$ (2) $\quad\Pi(x)=\sum\limits_{n\le x}\frac{\Lambda(n)}{\log(...
Steven Clark's user avatar
  • 7,631
1 vote
1 answer
353 views

Dirichlet density of $p \equiv 1 \bmod 8$

I am pretty new to this website although it looks really useful. Could someone help me please? My question is that same as this one: Computing the Dirichlet Density I can't work out how to calculate ...
JSharpee's user avatar
  • 533
2 votes
0 answers
483 views

Computing the Dirichlet Density

I have been asked the following question. I'm not even sure where to start. Compute the Dirichlet density of the set of all primes $p$ such that $2$, $-2$, and $-1$ are all squares modulo $p$.
PercyF2519's user avatar
1 vote
0 answers
164 views

Asymptotic for primitive Dirichlet characters over primes

The Polya-Vinogradov's inequality states that if $\chi$ is a primitive character mod $q$ then $|\sum_{n\le x}\chi(n)|\le \sqrt{q}\log q$. I now want to give the estimation for the sum over primes, i.e....
Teppi's user avatar
  • 173
0 votes
0 answers
77 views

On Dirichlet series and Firoozbakht's conjecture

On assumption of the Firoozbakht's conjecture (this is the Wikipedia, but the reference is for Carlos Rivera's Page) one has that can writes informally the Dirichlet series in LHS of this inequality $$...
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