1,3

Also numbers n such that (7*10^(n+1)-43)/9 is prime.

Index entries for primes involving repunits

Do[ If[ PrimeQ[70*(10^n - 1)/9 + 3], Print[n]], {n, 0, 5000}]

Sequence in context: A078649 A161607 A022442 this_sequence A034037 A033153 A086790

Adjacent sequences: A056686 A056687 A056688 this_sequence A056690 A056691 A056692

hard,nonn

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