English

Some identities involving the Ces\`aro average of Goldbach numbers

Number Theory 2018-02-20 v2

Abstract

Let Λ(n)\Lambda\left(n\right) be the von Mangoldt function and rG(n):=m1+m2=nΛ(m1)Λ(m2)r_{G}\left(n\right) := \sum_{m_1 + m_2=n} \Lambda \left(m_1 \right) \Lambda\left(m_2 \right) be the counting function for the numbers that can be written as sum of two primes (that we will call "Goldbach numbers", for brevity) and let S~(z):=n1Λ(n)enz\widetilde{S }\left(z\right) := \sum_{n\geq1} \Lambda\left(n\right) e^{-nz}, with zCz\in\mathbb{C}, Re(z)>0\mathrm{Re}\left(z\right)>0. In this paper we will prove the identity S~(z)=e2zzρzρΓ(ρ)+ρ(zργ(ρ,2z)2ρezρ)+G(z)\widetilde{S}\left(z\right) = \frac{e^{-2z}}{z}-\sum_{\rho}z^{-\rho} \Gamma \left(\rho\right) + \sum_{\rho} \left(z^{-\rho} \gamma\left(\rho,2z\right) - \frac{2^{\rho}e^{-z}}{\rho} \right) + G\left(z\right) where γ(ρ,2z)\gamma\left(\rho,2z\right) is the lower incomplete Gamma function, ρ=β+iγ\rho=\beta+i\gamma runs over the non-trivial zeros of the Riemann Zeta function and G(z)G\left(z\right) is a sum of (explicitly calculate) elementary function and complex Exponential integrals. In addition we will prove that \begin{align*} \sum_{n\leq N} r_G \left(n\right) \left(N-n\right) = & \frac{N^{3}}{6} - 2\sum_{\rho}\frac{\left(N-2\right)^{\rho+2}}{\rho\left(\rho + 1\right)\left(\rho+2\right)} + & \sum_{\rho_1} \sum_{\rho_2} \frac{\Gamma\left(\rho_{1}\right) \Gamma\left(\rho_{2}\right)} {\Gamma\left(\rho_{1} + \rho_{2}+ 2\right)} N^{\rho_1 + \rho_2+1} + F\left(N\right) \end{align*} where N>4N>4 is a natural number and F(N)F\left(N\right) is a sum of (explicitly calculate) elementary functions, dilogarithms and sums over non-trivial zeros of the Riemann Zeta function involving the incomplete Beta function.

Keywords

Cite

@article{arxiv.1711.08610,
  title  = {Some identities involving the Ces\`aro average of Goldbach numbers},
  author = {Marco Cantarini},
  journal= {arXiv preprint arXiv:1711.08610},
  year   = {2018}
}

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