# Cool-divisble numbers

Author: daniyar
Problem has been solved: 69 times

Русский язык | English Language

A number $\overline {a_1a_2 ... a_k}$ is said to be cool-divisible if, for any $n = 1,2, ..., k-1$, the number $\overline {a_na_ {n + 1}}$ is divisible by 17 or 23. Find the number of 2020-digit cool-divisible numbers.