A062636 - OEIS

%I #20 Jul 04 2021 09:00:09

%S 2,11,1301,78989,83117

%N Numbers k such that 70^k - 69^k is prime.

%C Terms greater than 1000 are often only strong pseudoprimes.

%C a(6) > 10^5. - _Robert Price_ Jan 15 2014

%o (PARI) is(n)=ispseudoprime(70^n-69^n) \\ _Charles R Greathouse IV_, Jun 13 2017

%Y Cf. A000043, A057468, A059801, A059802, A062572-A062666.

%K nonn,hard,bref

%O 1,1

%A _Mike Oakes_, May 18 2001, May 19 2001

%E a(4)-a(5) from _Robert Price_, Jan 15 2014 (Computer run by Adam Marciniec)