1,2

Also numbers n such that (25*10^n+11)/9 is prime.

Makoto Kamada, Factorizations of 277...779.

Index entries for primes involving repunits.

Do[ If[ PrimeQ[(25*10^n + 11)/9], Print[n]], {n, 0, 10000}]

Sequence in context: A113086 A058153 A020197 this_sequence A057959 A053902 A054464

Adjacent sequences: A102956 A102957 A102958 this_sequence A102960 A102961 A102962

more,nonn

Robert G. Wilson v (rgwv(AT)rgwv.com), Dec 17 2004