# Repdigit

Repdigits are the representation in base ${\displaystyle B}$ of the number ${\displaystyle x{\frac {B^{y}-1}{B-1}}}$ where ${\displaystyle 0 is the repeated digit and ${\displaystyle y}$ is the number of repetitions. For example, the repdigit 77 in base 10 is ${\displaystyle 7\times {\frac {10^{2}-1}{10-1}}}$.