MathDB
perfect square +1000= other perfect square +1

Source: OLCOMA Costa Rica National Olympiad, Final Round, 2016 Shortlist A2 day2

September 24, 2021
number theoryPerfect SquaresPerfect Square

Problem Statement

The initial number of inhabitants of a city of more than 150150 inhabitants is a perfect square. With an increase of 10001000 inhabitants it becomes a perfect square plus a unit. After from another increase of 10001000 inhabitants it is again a perfect square. Determine the quantity of inhabitants that are initially in the city.