MathDB

caa...ab is always composite

Source: Saint Petersburg olympiad 2024, 11.4

September 22, 2024

number theory

Problem Statement

Given a

101

-digit number

a

and an arbitrary positive integer

b

. Prove that there is at most a

102

-digit positive integer

c

such that any number of the form

\overline{caaa \dots ab}

is composite.

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