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On Solving a Curious Inequality of Ramanujan

Number Theory 2014-07-09 v1

Abstract

Ramanujan proved that the inequality π(x)2<exlogxπ(xe)\pi(x)^2 < \frac{e x}{\log x} \pi\Big(\frac{x}{e}\Big) holds for all sufficiently large values of xx. Using an explicit estimate for the error in the prime number theorem, we show unconditionally that it holds if xexp(9658)x \geq \exp(9658). Furthermore, we solve the inequality completely on the Riemann Hypothesis, and show that x=38,358,837,682x=38, 358, 837, 682 is the largest integer counterexample.

Cite

@article{arxiv.1407.1901,
  title  = {On Solving a Curious Inequality of Ramanujan},
  author = {Dave Platt and Adrian Dudek},
  journal= {arXiv preprint arXiv:1407.1901},
  year   = {2014}
}

Comments

11 pages, 1 figure; feedback welcome

R2 v1 2026-06-22T04:57:37.624Z