Aiichi Yamasaki's Homepage



A reepunit is an integer of the form Rn=(10n-1)/9. It consists of n copies of the digit 1 in decimal representation. Rn is proved to be prime for n=2,19,23,317,1031. R49081 and R86453 are probably prime. It has been conjectured that there are infinitely many repunit primes.

factorization of repunit up to R100

repunits and Kaprekar numbers