English

The n-th prime exponentially

Number Theory 2025-06-17 v1

Abstract

From known effective bounds on the prime counting function of the form π(x)Li(x)<a  x  (lnx)b  exp(c  lnx);(xx0); |\pi(x)-\mathrm{Li}(x)| < a \;x \;(\ln x)^{b} \; \exp\left(-{c}\; \sqrt{\ln x}\right); \qquad (x \geq x_0); it is possible to establish exponentially tight effective upper and lower bounds on the prime number theorem: For xxx \geq x_* where xmax{x0,17}x_*\leq \max\{x_0,17\} we have: Li1+a  (lnx)b+1  exp(c  lnx)<π(x)<Li1a  (lnx)b+1  exp(c  lnx). {\mathrm{Li} \over 1+a\; (\ln x)^{b+1} \; \exp\left(-c\; \sqrt{\ln x}\right)} < \pi(x) < {\mathrm{Li} \over 1-a \;(\ln x)^{b+1} \; \exp\left(-c\; \sqrt{\ln x}\right)}. Furthermore, it is possible to establish exponentially tight effective upper and lower bounds on the location of the nthn^{th} prime. Specifically: pn<Li1(n[1+a  (ln[nlnn])b+1  exp(c  ln[nlnn])]);(nn). p_n < \mathrm{Li}^{-1} \left( n \left[1+ a \;(\ln[n\ln n])^{b+1} \; \exp\left(-{c}\; \sqrt{\ln[n\ln n]}\right)\right] \right); \qquad (n\geq n_*). pn>Li1(n[1a  (ln[nlnn])b+1  exp(c  ln[nlnn])]);(nn). p_n > \mathrm{Li}^{-1} \left( n \left[1- a \;(\ln[n\ln n])^{b+1} \; \exp\left(-{c}\; \sqrt{\ln[n\ln n]}\right)\right] \right); \qquad (n\geq n_*). Here the range of validity is explicitly bounded by some nn_* satisfying nmax{π(x0),π(17),π((1+e1)exp([2(b+1)c]2))}. n_* \leq \max\left\{\pi(x_0),\pi(17), \pi\left( (1+e^{-1}) \exp\left( \left[2(b+1)\over c\right]^2\right)\right) \right\}. Many other fully explicit bounds along these lines can easily be developed.

Keywords

Cite

@article{arxiv.2504.14458,
  title  = {The n-th prime exponentially},
  author = {Matt Visser},
  journal= {arXiv preprint arXiv:2504.14458},
  year   = {2025}
}

Comments

11 pages; 5 tables; no figures

R2 v1 2026-06-28T23:04:30.689Z