1,2

Also numbers n such that (23*10^n+31)/9 is prime.

Makoto Kamada, Factorizations of 255...559.

Index entries for primes involving repunits.

Do[ If[ PrimeQ[(23*10^n + 31)/9], Print[n]], {n, 0, 10000}]

Sequence in context: A092229 A048513 A116341 this_sequence A031696 A005972 A082972

Adjacent sequences: A102953 A102954 A102955 this_sequence A102957 A102958 A102959

more,nonn

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