1,2

Also numbers n such that (2*10^n+43)/9 is prime.

Index entries for primes involving repunits

Do[ If[ PrimeQ[ 2(10^n - 1)/9 + 5], Print[n]], {n, 5000}]

Sequence in context: A131822 A131801 A122819 this_sequence A002127 A061810 A048701

Adjacent sequences: A099406 A099407 A099408 this_sequence A099410 A099411 A099412

nonn

Robert G. Wilson v (rgwv(AT)rgwv.com), Oct 14 2004