1,2

Also numbers n such that (28*10^n+71)/9 is prime.

Makoto Kamada, Factorizations of 311...119.

Index entries for primes involving repunits.

Do[ If[ PrimeQ[(28*10^n+71)/9], Print[n]], {n, 0, 10000}]

Sequence in context: A050819 A037121 A162363 this_sequence A100931 A152180 A042135

Adjacent sequences: A102962 A102963 A102964 this_sequence A102966 A102967 A102968

more,nonn

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

Two more PRP terms from Serge Batalov (batalovs(AT)yahoo.com), Nov 17 2008