IMO 2022 Shortlist A1

Let panqně1 be a sequence of positive real numbers with the property that pan1q2 anan2 ď an an2 for all positive integer...

IMO 2022 Shortlist A1

Category: Algebra

Problem

Let panqně1 be a sequence of positive real numbers with the property that pan1q2 anan2 ď an an`2 for all positive integers n. Show that a2022 ď 1. (Nigeria)