This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A128342 #13 Nov 01 2018 21:26:46
%S A128342 13,19,31,359,487,757,761,1667,2551,3167,6829
%N A128342 Numbers k such that (13^k + 5^k)/18 is prime.
%C A128342 All terms are primes.
%C A128342 No other terms below 23600. - _Max Alekseyev_, Feb 01 2010
%C A128342 a(12) > 10^5. - _Robert Price_, Apr 30 2013
%t A128342 k=13; Do[p=Prime[n]; f=(k^p+5^p)/(k+5); If[ PrimeQ[f], Print[p] ], {n,1,100}]
%o A128342 (PARI) is(n)=isprime((13^n+5^n)/18) \\ _Charles R Greathouse IV_, Feb 17 2017
%Y A128342 Cf. A057171, A082387, A122853, A128335, A128336, A128337, A128338, A128339, A128340, A128341, A128343. Cf. A004061, A082182, A121877, A059802. Cf. A062572, A128344, A128345, A128346, A128347, A128348, A128349, A128350, A128351, A128352, A128353, A128354.
%K A128342 hard,more,nonn
%O A128342 1,1
%A A128342 _Alexander Adamchuk_, Feb 27 2007
%E A128342 Four more terms from _Max Alekseyev_, Feb 01 2010