The largest known repunit prime is equal to R49,081 = (1049,081 − 1) / 9 which is 49,081 digits long; Harvey Dubner discovered it as a probable prime in 1999[1] and its primality was proven in March 2022 by Paul Underwood.[2][3]
The largest known repunit probable prime is equal to R8,177,207 = (108,177,207 − 1) / 9 which is 8,177,207 digits long; it has been discovered on May 2021.[4]
Sources[]
- ↑ The Top Twenty: Repunit
- ↑ R(49081) - PrimePages (retrieved 2023-05-16)
- ↑ Paul Underwood's post at mersenneforum.org (retrieved 2023-01-10)
- ↑ Henri & Renaud Lifchitz's PRP Top - Search for : (10^?-1)/9 (retrieved 2021-06-05)