A Question of Erd\H{o}s and Graham on Covering Systems
A Question of Erd\H{o}s and Graham on Covering Systems
Erd\H{o}s and Graham (Erd\H{o}s and Graham, 1980) asked if there exists an $n$ such that the divisors of $n$ greater than 1 are the moduli of a distinct covering system with the following property: If there exists an integer which satisfies two congruences in the system, $a\mod d$ and $a'\mod …