1,2

Also numbers n such that (67*10^n-31)/9 is prime.

Makoto Kamada, Factorizations of 744...441.

Index entries for primes involving repunits.

Do[ If[ PrimeQ[(67*10^n - 31)/9], Print[n]], {n, 0, 10000}]

Sequence in context: A107622 A049306 A023635 this_sequence A039590 A110605 A102140

Adjacent sequences: A103054 A103055 A103056 this_sequence A103058 A103059 A103060

more,nonn

Robert G. Wilson v (rgwv(AT)rgwv.com), Jan 19 2005