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As the title suggests, I am looking for conjectures involving the Von Mangoldt function, $\Lambda(n)$. I understand this is not a rigorous mathematical question, however if reference requests for conjectures and theorems are permitted, then I humbly ask this question to be considered and approved here. I will make sure to include appropriate tags. I am looking specifically for conjectures that can be written in terms of $\Lambda(n)$, like for example: Goldbach's conjecture rewritten, or conjectures about the nature of $\Lambda(n)$. The reason is to attempt solving something in number theory, and find $\Lambda(n)$ to have some nice analytic properties/connections to the broader number theory. Thank you

Mako
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    To my untrained eyes there seems to be one at https://oeis.org/wiki/Von_Mangoldt_function. – A rural reader Jul 10 '24 at 16:50
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    @Aruralreader If I'm not mistaken, it conjectures that $$\text{GCD}(\binom{n}{1}, \binom{n}{2}, \ldots, \binom{n}{n-1}) = e^{\Lambda(n)}$$, right? I have never seen this before. Thank you for pointing this out +1 – Mako Jul 10 '24 at 16:58
  • @Aruralreader It seems a consequence of this, nevertheless interesting though – Mako Jul 10 '24 at 17:09
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    Virtually every conjecture about primes can be rephrased in terms of the von Mangoldt function. For example, the quantitative twin primes conjecture is equivalent to an asymptotic formula for $\sum_{n\le x} \Lambda(n)\Lambda(n+2)$. – Greg Martin Jul 13 '24 at 17:27
  • @GregMartin Well aware, it is what I'm looking for :) – Mako Jul 16 '24 at 16:25
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    https://math.stackexchange.com/questions/153697/the-goldbach-conjecture-and-hardy-littlewood-asymptotic#:~:text=Here%2C%20Λ(n)%20denotes,behaviour%20may%20depend%20on%20A. – Martin.s Jul 17 '24 at 18:20

1 Answers1

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The following has been proven by joriki and GH from MO: $$n>1:$$ $$\Lambda(n)=\lim\limits_{s \rightarrow 1} \zeta(s)\sum\limits_{d|n} \frac{\mu(d)}{d^{(s-1)}}$$

$$a(n) = -\lim\limits_{s \rightarrow 1} \zeta(s)\sum\limits_{d|n} \mu(d)(e^{d})^{(s-1)}$$

$$T(n,k) = a(GCD(n,k))$$

$$\displaystyle T = \begin{bmatrix} +1&+1&+1&+1&+1&+1&+1&\cdots \\ +1&-1&+1&-1&+1&-1&+1 \\ +1&+1&-2&+1&+1&-2&+1 \\ +1&-1&+1&-1&+1&-1&+1 \\ +1&+1&+1&+1&-4&+1&+1 \\ +1&-1&-2&-1&+1&+2&+1 \\ +1&+1&+1&+1&+1&+1&-6 \\ \vdots&&&&&&&\ddots \end{bmatrix}$$

which gives a symmetric expansion of the von Mangoldt function:

$$\displaystyle \begin{bmatrix} \frac{T(1,1)}{1 \cdot 1}&+\frac{T(1,2)}{1 \cdot 2}&+\frac{T(1,3)}{1 \cdot 3}+&\cdots&+\frac{T(1,k)}{1 \cdot k} \\ \frac{T(2,1)}{2 \cdot 1}&+\frac{T(2,2)}{2 \cdot 2}&+\frac{T(2,3)}{2 \cdot 3}+&\cdots&+\frac{T(2,k)}{2 \cdot k} \\ \frac{T(3,1)}{3 \cdot 1}&+\frac{T(3,2)}{3 \cdot 2}&+\frac{T(3,3)}{3 \cdot 3}+&\cdots&+\frac{T(3,k)}{3 \cdot k} \\ \vdots&\vdots&\vdots&\ddots&\vdots \\ \frac{T(n,1)}{n \cdot 1}&+\frac{T(n,2)}{n \cdot 2}&+\frac{T(n,3)}{n \cdot 3}+&\cdots&+\frac{T(n,k)}{n \cdot k} \end{bmatrix} = \begin{bmatrix} \frac{\infty}{1} \\ +\frac{\Lambda(2)}{2} \\ +\frac{\Lambda(3)}{3} \\ \vdots \\ +\frac{\Lambda(n)}{n} \end{bmatrix}$$

$$=\;\;\;\;\;\;\;\;\;\;\;$$

$$\displaystyle \begin{bmatrix} \frac{\infty}{1}&+\frac{\Lambda(2)}{2}&+\frac{\Lambda(3)}{3}+&\cdots&+\frac{\Lambda(k)}{k} \end{bmatrix}\;\;\;\;\;\;\;\;\;\;\;$$

The generating function for the matrix $T$ is:

$$\sum\limits_{k=1}^{\infty}\sum\limits_{n=1}^{\infty} \frac{T(n,k)}{n^c \cdot k^s} = \sum\limits_{n=1}^{\infty} \frac{\lim\limits_{z \rightarrow s} \zeta(z)\sum\limits_{d|n} \frac{\mu(d)}{d^{(z-1)}}}{n^c} = \frac{\zeta(s) \zeta(c)}{\zeta(s + c - 1)}$$

The generating function for the main diagonal of the matrix $T$ is: $$\sum_{n=1}^{\infty} \frac{T(n,n)}{n^s}=\frac{\zeta (s)}{\zeta (s-1)}$$

Set $c=s$ and add the generating functions together and take the limit:

$$\underset{s\to 1}{\text{lim}}\left(\frac{\zeta (s) \zeta (s)}{\zeta (s+s-1)}+\frac{\zeta (s)}{\zeta (s-1)}\right)=-2 \gamma+2 \log (2 \pi )$$

But that is not the same as the reciprocal sum over the zeta zeros:

RH Equivalence 5.3, page 6. The Riemann Hypothesis is equivalent to the equality:

$$\sum_{\rho} \frac{1}{|\rho|^2} =\sum_{\rho} \frac{1}{\rho (1{-}\rho)}= 2 + \gamma - \log (4\pi)$$

where the sum is over all complex zeros $$ρ = β + iγ$$ of $$ζ(s)$$ in the critical strip $$0 < β < 1$$.

Edit 21.8.2024:

The Riemann hypothesis is equivalent to:

$$\underset{\text{factor}}{-2}\left(\underset{\text{non-trivial zeros}}{\sum_{\rho} \frac{1}{\rho (1{-}\rho)}} + \underset{\text{trivial zeros}}{\sum_{k \geq 1} \frac{1}{-2k(1-(-2k))}} - \underset{\text{the pole}}{1}\right)= \underset{s\to 1}{\text{lim}}\left(\underset{\text{the whole matrix}}{\frac{\zeta (s) \zeta (s)}{\zeta (s+s-1)}}+\underset{\text{main diagonal}}{\frac{\zeta (s)}{\zeta (s-1)}}\right)$$

Where: $$\underset{\text{the whole matrix}}{\frac{\zeta (s) \zeta (s)}{\zeta (s+s-1)}}$$ is a Dirichlet generating function which when evaluated at $s=1$ as in the limit (above) is the symmetric expansion of the von Mangoldt function above.


Series expansions in Mathematica 14:

Series expansions in Mathematica 14

Mats Granvik
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    Limit[Zeta[s]*Zeta[s]/Zeta[s + s - 1] + Zeta[s]/Zeta[s - 1], s -> 1] == -2 EulerGamma + 2 Log[2 \[Pi]] – Mats Granvik Jul 21 '24 at 12:56
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    $$\underset{s\to 1}{\text{lim}}\left(\frac{\zeta (s) \zeta (s)}{\zeta (s+s-1)}+\frac{\zeta (s)}{\zeta (s-1)}\right)=-2 \gamma+2 \log (2 \pi )$$

    $$\sum_{\rho} \frac{1}{|\rho|^2} =\sum_{\rho} \frac{1}{\rho (1{-}\rho)}= 2 + \gamma - \log (4\pi)$$

    $$\sum_{k=1}^{k=\infty} \frac{1}{-2k(1-(-2k))} = \log (2)-1$$

    – Mats Granvik Jul 23 '24 at 19:18
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    Excel recurrence for T: =IF(OR(ROW()=1; COLUMN()=1); 1; IF(ROW()>=COLUMN();-SUM(INDIRECT(ADDRESS(ROW()-COLUMN()+1;COLUMN(); 4)&":"&ADDRESS(ROW()-1; COLUMN(); 4); 4));-SUM(INDIRECT(ADDRESS(COLUMN()-ROW()+1;ROW(); 4)&":"&ADDRESS(COLUMN()-1; ROW(); 4); 4)))) or with different separator commas: =IF(OR(ROW()=1, COLUMN()=1), 1, IF(ROW()>=COLUMN(),-SUM(INDIRECT(ADDRESS(ROW()-COLUMN()+1,COLUMN(), 4)&":"&ADDRESS(ROW()-1, COLUMN(), 4), 4)),-SUM(INDIRECT(ADDRESS(COLUMN()-ROW()+1,ROW(), 4)&":"&ADDRESS(COLUMN()-1, ROW(), 4), 4)))) Excel formula translator: https://de.excel-translator.de/translator/ – Mats Granvik Aug 21 '24 at 14:31
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    I greatly appreciate all the effort you've put into this post. I wish I could like this answer twice! – Mako Aug 21 '24 at 21:35
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    Thank you for the kind words! – Mats Granvik Aug 22 '24 at 12:02
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    Normal[Series[Zeta[s]*Zeta[s]/Zeta[s + s - 1], {s, 1, 0}]] Series1 Normal[Series[Zeta[s]/Zeta[s - 1], {s, 1, 0}]] Series2 – Mats Granvik Aug 22 '24 at 12:10