1,1

Also numbers n such that (10^n+71)/9 is prime.

Values indicate primes of the form "(n-1) ones followed by a nine". Related to the base 10 repunit primes.

Index entries for primes involving repunits

Do[ If[ PrimeQ[(10^n - 1)/9 + 8], Print[n]], {n, 0, 5000}] (from Robert G. Wilson v Oct 14 2004)

Equals A056659 + 1. Cf. A004023, A097683, A097684.

Sequence in context: A045547 A127143 A079256 this_sequence A136369 A007573 A143909

Adjacent sequences: A097682 A097683 A097684 this_sequence A097686 A097687 A097688

nonn

Carl R. White (cyrek(AT)cyreksoft.yorks.com), Aug 19 2004