An algorithm and computation to verify Legendre's Conjecture up to $3.33\cdot10^{13}$

Fuente: arXiv
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Main Authors: Sorenson, Jonathan, Webster, Jonathan
Format: Preprint
Published: 2024
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author Sorenson, Jonathan
Webster, Jonathan
author_facet Sorenson, Jonathan
Webster, Jonathan
contents We state a general purpose algorithm for quickly finding primes in evenly divided sub-intervals. Legendre's conjecture claims that for every positive integer $n$, there exists a prime between $n^2$ and $(n+1)^2$. Oppermann's conjecture subsumes Legendre's conjecture by claiming there are primes between $n^2$ and $n(n+1)$ and also between $n(n+1)$ and $(n+1)^2$. Using Cramér's conjecture as the basis for a heuristic run-time analysis, we show that our algorithm can verify Oppermann's conjecture, and hence also Legendre's conjecture, for all $n\le N$ in time $O( N \log N \log \log N)$ and space $N^{O(1/\log \log N)}$. We implemented a parallel version of our algorithm and improved the empirical verification of Oppermann's conjecture from the previous $N = 2\cdot 10^{9}$ up to $N = 3.33\cdot 10^{13}$, so we were finding $27$ digit primes. The computation ran for about half a year on four Intel Xeon Phi $7210$ processors using a total of $256$ cores.
format Preprint
id arxiv_https___arxiv_org_abs_2401_13753
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle An algorithm and computation to verify Legendre's Conjecture up to $3.33\cdot10^{13}$
Sorenson, Jonathan
Webster, Jonathan
Number Theory
11A41, 11Y16, 11Y55, 68Q25
We state a general purpose algorithm for quickly finding primes in evenly divided sub-intervals. Legendre's conjecture claims that for every positive integer $n$, there exists a prime between $n^2$ and $(n+1)^2$. Oppermann's conjecture subsumes Legendre's conjecture by claiming there are primes between $n^2$ and $n(n+1)$ and also between $n(n+1)$ and $(n+1)^2$. Using Cramér's conjecture as the basis for a heuristic run-time analysis, we show that our algorithm can verify Oppermann's conjecture, and hence also Legendre's conjecture, for all $n\le N$ in time $O( N \log N \log \log N)$ and space $N^{O(1/\log \log N)}$. We implemented a parallel version of our algorithm and improved the empirical verification of Oppermann's conjecture from the previous $N = 2\cdot 10^{9}$ up to $N = 3.33\cdot 10^{13}$, so we were finding $27$ digit primes. The computation ran for about half a year on four Intel Xeon Phi $7210$ processors using a total of $256$ cores.
title An algorithm and computation to verify Legendre's Conjecture up to $3.33\cdot10^{13}$
topic Number Theory
11A41, 11Y16, 11Y55, 68Q25
url https://arxiv.org/abs/2401.13753