1,2

Also numbers n such that (71*10^n+1)/9 is prime.

Makoto Kamada, Factorizations of 788...889.

Index entries for primes involving repunits.

Do[ If[ PrimeQ[(71*10^n + 1)/9], Print[n]], {n, 0, 10000}]

Sequence in context: A099565 A063563 A166749 this_sequence A080519 A120407 A033166

Adjacent sequences: A103064 A103065 A103066 this_sequence A103068 A103069 A103070

more,nonn

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