MathDB
Polynomial-ish divisibility problem

Source: Kvant Magazine No. 10 2023 M2768

February 6, 2024
number theoryDivisibility

Problem Statement

Let nn{} be a natural number. The pairwise distinct nonzero integers a1,a2,,ana_1,a_2,\ldots,a_n have the property that the number (k+a1)(k+a2)(k+an)(k+a_1)(k+a_2)\cdots(k+a_n)is divisible by a1a2ana_1a_2\cdots a_n for any integer k.k{}. Find the largest possible value of an.a_n.
Proposed by F. Petrov and K. Sukhov