MathDB
Sequence with floor function

Source: Romanian District Olympiad 2024 11.2

March 10, 2024
Sequenceslimitanalysis

Problem Statement

Let k2k\geqslant 2 be an integer. Consider the sequence (xn)n1(x_n)_{n\geqslant 1} defined by x1=a>0x_1=a>0 and xn+1=xn+k/xnx_{n+1}=x_n+\lfloor k/x_n\rfloor for n1.n\geqslant 1. Prove that the sequence is convergent and determine its limit.