1,2

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

Makoto Kamada, Factorizations of 344...447.

Index entries for primes involving repunits.

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

Sequence in context: A090565 A072384 A109949 this_sequence A078169 A109555 A013537

Adjacent sequences: A102966 A102967 A102968 this_sequence A102970 A102971 A102972

more,nonn

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