MathDB
99 % of 2000 numbers, composite - All-Russian MO 2000 Regional (R4) 10.1

Source:

September 26, 2024
number theoryComposite

Problem Statement

20002000 numbers are considered: 11,101,1001,..11, 101, 1001, . . . Prove that at least 99%99\% of these numbers are composite.