Investigate Mersenne numbers with Rust Numbers of the form $M_n=2^n-1$ are called Mersenne numbers. If $M_n$ is prime, $n$ is also prime, but the converse is not true. The smallest counterexample is $M_{11}=2047=23\cdot 89$. Mersenne prime - Wikipedia This repository contains Rust codes using arbitrary-precision arithmetics to find Mersenne numbers .