MathDB
[ \sqrt{n} ] + [ n / [ \sqrt{n} ] ] > 2 \sqrt{n}

Source: (2022 -) 2023 XVI Dürer Math Competition Regional E+1

May 25, 2024
algebrainequalitiesfloor function

Problem Statement

Find all positive integers nn such that n+nn>2n.\lfloor \sqrt{n} \rfloor + \left\lfloor \frac{n}{\lfloor \sqrt{n} \rfloor} \right \rfloor> 2\sqrt{n}. If kk is a real number, then k\lfloor k \rfloor means the floor of kk, this is the greatest integer less than or equal to kk.