# 317/Mistake

< 317

## Source Work

The Dictionary
$11,111,111, \ldots 111,111$

## Mistake

The $3$rd known prime repunit.

## Correction

The $4$th known, in fact, after $R_2$, $R_{19}$ and $R_{23}$.

This mistake does not appear in Curious and Interesting Numbers of $1986$, where it states:

The $4$th and largest known prime repunit.

Some considerably larger ones have been discovered since.