IMO 2018 Shortlist A2

Find all positive integers n ě 3 for whi h there exist real numbers a1,a2,...,an, an1 “ a1, an2 “ a2 su h that aiai1 1 “...

IMO 2018 Shortlist A2

Category: Algebra

Problem

Find all positive integers n ě 3 for whi h there exist real numbers a1,a2,...,an, an1 “ a1, an2 “ a2 su h that aiai1 1 “ ai`2 for all i “ 1,2,...,n. (Slovakia)