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Numbers n such that 10^n*(3+7*10^n)+7 is prime.
0

%I #4 Dec 15 2017 17:37:11

%S 0,10,18,222,1150,7180

%N Numbers n such that 10^n*(3+7*10^n)+7 is prime.

%C The value corresponding to n=7180 was certified a Fermat and Lucas PRP with WinPFGW and submitted to Lifchitz's Top PRPs database.

%o (PARI) is(n)=ispseudoprime(10^n*(3+7*10^n)+7) \\ _Charles R Greathouse IV_, Jun 13 2017

%K more,nonn

%O 1,2

%A _Jason Earls_, Dec 18 2009