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<=100 perfect squares - All-Russian MO 2001 Regional (R4) 9.8

Source:

September 26, 2024
number theoryPerfect SquareDigits

Problem Statement

Sasha wrote a non-zero number on the board and added it to it on the right, one non-zero digit at a time, until he writes out a million digits. Prove that an exact square has been written on the board no more than 100100 times.