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 A128338 #10 Nov 01 2018 21:25:43
%S A128338 7,19,167,173,223,281,21647
%N A128338 Numbers k such that (8^k + 5^k)/13 is prime.
%C A128338 All terms are primes.
%C A128338 a(8) > 10^5. - _Robert Price_, Jan 21 2013
%t A128338 k=8; Do[p=Prime[n]; f=(k^p+5^p)/(k+5); If[ PrimeQ[f], Print[p] ], {n,1,100}]
%o A128338 (PARI) is(n)=isprime((8^n+5^n)/13) \\ _Charles R Greathouse IV_, Feb 17 2017
%Y A128338 Cf. A057171, A082387, A122853, A128335, A128336, A128337, A128339, A128340, A128341, A128342, A128343. Cf. A004061, A082182, A121877, A059802. Cf. A062572, A128344, A128345, A128346, A128347, A128348, A128349, A128350, A128351, A128352, A128353, A128354.
%K A128338 hard,more,nonn
%O A128338 1,1
%A A128338 _Alexander Adamchuk_, Feb 27 2007
%E A128338 a(7) from _Robert Price_, Jan 21 2013