English

A Ces\`aro Average of Hardy-Littlewood numbers

Number Theory 2018-06-22 v1

Abstract

Let Λ\Lambda be the von Mangoldt function and rHL(n)=m1+m22=nΛ(m1),r_{\textit{HL}}(n) = \sum_{m_1 + m_2^2 = n} \Lambda(m_1), be the counting function for the Hardy-Littlewood numbers. Let NN be a sufficiently large integer. We prove that nNrHL(n)(1n/N)kΓ(k+1)=π1/22N3/2Γ(k+5/2)12NΓ(k+2)π1/22ρΓ(ρ)Γ(k+3/2+ρ)N1/2+ρ+1/2ρΓ(ρ)Γ(k+1+ρ)Nρ+N3/4k/2πk+11Jk+3/2(2πN1/2)k+3/2N1/4k/2πkρΓ(ρ)Nρ/2πρ1Jk+1/2+ρ(2πN1/2)k+1/2+ρ+Ok(1).\begin{align}\sum_{n \le N} r_{\textit{HL}}(n) \frac{(1 - n/N)^k}{\Gamma(k + 1)} &= \frac{\pi^{1 / 2}}2 \frac{N^{3 / 2}}{\Gamma(k + 5 / 2)} - \frac 12 \frac{N}{\Gamma(k + 2)} - \frac{\pi^{1 / 2}}2 \sum_{\rho} \frac{\Gamma(\rho)}{\Gamma(k + 3 / 2 + \rho)} N^{1 / 2 + \rho}\\ &+ 1/2 \sum_{\rho} \frac{\Gamma(\rho)}{\Gamma(k + 1 + \rho)} N^{\rho} + \frac{N^{3 / 4 - k / 2}}{\pi^{k + 1}} \sum_{\ell \ge 1} \frac{J_{k + 3 / 2} (2 \pi \ell N^{1 / 2})}{\ell^{k + 3 / 2}}\\ &- \frac{N^{1 / 4 - k / 2}}{\pi^k} \sum_{\rho} \Gamma(\rho) \frac{N^{\rho / 2}}{\pi^\rho} \sum_{\ell \ge 1} \frac{J_{k + 1 / 2 + \rho} (2 \pi \ell N^{1 / 2})} {\ell^{k + 1 / 2 + \rho}} + \mathcal{O}_k(1).\end{align} for k>1k > 1, where ρ\rho runs over the non-trivial zeros of the Riemann zeta-function ζ(s)\zeta(s) and Jν(u)J_{\nu} (u) denotes the Bessel function of complex order ν\nu and real argument uu.

Keywords

Cite

@article{arxiv.1206.0255,
  title  = {A Ces\`aro Average of Hardy-Littlewood numbers},
  author = {Alessandro Languasco and Alessandro Zaccagnini},
  journal= {arXiv preprint arXiv:1206.0255},
  year   = {2018}
}

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