1,2

Also numbers n such that (46*10^n-1)/9 is prime.

Makoto Kamada, Factorizations of 511...11

Index entries for primes involving repunits

Do[ If[ PrimeQ[ 5*10^n + (10^n-1)/9], Print[n]], {n, 0, 10000}]

Sequence in context: A009824 A087090 A161756 this_sequence A110670 A111523 A078231

Adjacent sequences: A056710 A056711 A056712 this_sequence A056714 A056715 A056716

hard,nonn

Robert G. Wilson v (rgwv(AT)rgwv.com), Aug 11 2000

8687 from Hugo Pfoertner, Oct 19 2004