1,2

Also numbers n such that (8*10^(n+1)+1)/9 is prime.

Index entries for primes involving repunits

Do[ If[ PrimeQ[ 80*(10^n - 1)/9 + 9 ], Print[n]], {n, 0, 30000}]

Sequence in context: A064805 A110623 A132947 this_sequence A103230 A107081 A029526

Adjacent sequences: A056660 A056661 A056662 this_sequence A056664 A056665 A056666

hard,nonn

Robert G. Wilson v (rgwv(AT)rgwv.com), Aug 09 2000