1,2

Also numbers n such that (56*10^n-11)/9 is prime.

Makoto Kamada, Factorizations of 622...221.

Index entries for primes involving repunits.

Do[ If[ PrimeQ[(56*10^n - 11)/9], Print[n]], {n, 0, 10000}]

Sequence in context: A014140 A103439 A147321 this_sequence A001698 A029761 A009337

Adjacent sequences: A103027 A103028 A103029 this_sequence A103031 A103032 A103033

more,nonn

Robert G. Wilson v (rgwv(AT)rgwv.com), Jan 18 2005