1,2

Also numbers n such that (4*10^n-31)/9 is prime.

Index entries for primes involving repunits

Do[ If[ PrimeQ[ 4(10^n - 1)/9 - 3], Print[n]], {n, 0, 7000}]

Sequence in context: A148130 A131482 A148131 this_sequence A100094 A099525 A024742

Adjacent sequences: A099409 A099410 A099411 this_sequence A099413 A099414 A099415

nonn

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