1,3

Also numbers n such that (34*10^n-7)/9 is prime.

Makoto Kamada, Factorizations of 377...77

Index entries for primes involving repunits

Do[ If[ PrimeQ[ 3*10^n + 7*(10^n-1)/9], Print[n]], {n, 0, 30070}]

Sequence in context: A166655 A146446 A132092 this_sequence A065706 A078874 A162555

Adjacent sequences: A056702 A056703 A056704 this_sequence A056706 A056707 A056708

hard,nonn

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