%I #9 Aug 12 2019 23:28:26

%S 5,13,97,1499,11321,320483

%N Numbers k such that (121^k + 1)/122 is prime.

%C The corresponding primes are terms of A059055. - _Bernard Schott_, Aug 09 2019

%t Do[p=Prime[n]; If[PrimeQ[(121^p + 1)/122], Print[p]], {n, 1, 1000000}]

%o (PARI) is(n)=ispseudoprime((121^n+1)/122)

%Y Cf. A059055.

%K nonn,more

%O 1,1

%A _Paul Bourdelais_, Aug 06 2019