1,3

Also numbers n such that (32*10^n+13)/9 is prime.

Makoto Kamada, Factorizations of 355...557.

Index entries for primes involving repunits.

Do[ If[ PrimeQ[(32*10^n+13)/9], Print[n]], {n, 0, 10000}]

Adjacent sequences: A102969 A102970 A102971 this_sequence A102973 A102974 A102975

Sequence in context: A026079 A066710 A033648 this_sequence A075209 A075207 A136121

more,nonn

Robert G. Wilson v (rgwv(AT)rgwv.com), Dec 17 2004