MathDB
Function involving floors

Source: Central American Olympiad 2006, Problem 3

April 30, 2007
functionfloor functionalgebra proposedalgebra

Problem Statement

For every natural number nn we define f(n)=n+n+12f(n)=\left\lfloor n+\sqrt{n}+\frac{1}{2}\right\rfloor Show that for every integer k1k \geq 1 the equation f(f(n))f(n)=kf(f(n))-f(n)=k has exactly 2k12k-1 solutions.