Problem

Source: Romanian IMO TST 2005 - day 2, problem 3

Tags: function, induction, algebra proposed, algebra



A sequence of real numbers {an}n is called a bs sequence if an=|an+1an+2|, for all n0. Prove that a bs sequence is bounded if and only if the function f given by f(n,k)=anak(anak), for all n,k0 is the null function. Mihai Baluna - ISL 2004