1,3

Also numbers n such that (5*10^(n+1)-23)/9 is prime.

Index entries for primes involving repunits

Do[ If[ PrimeQ[50*(10^n - 1)/9 + 3], Print[n]], {n, 0, 5000}]

Sequence in context: A118396 A001845 A127765 this_sequence A001296 A000970 A048477

Adjacent sequences: A056682 A056683 A056684 this_sequence A056686 A056687 A056688

hard,nonn

Robert G. Wilson v (rgwv(AT)rgwv.com), Aug 10 2000