MathDB
Paraguayan National Olympiad 2010, Level 3, Problem 4

Source:

September 20, 2014

Problem Statement

Find all 4-digit numbers abcd\overline{abcd} that are multiples of 1111, such that the 2-digit number ac\overline{ac} is a multiple of 77 and a+b+c+d=d2a + b + c + d = d^2.