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 A231329 #7 Jun 13 2017 14:28:46 %S A231329 7,11,211,14461 %N A231329 Numbers n such that (19^n + 4^n)/23 is prime. %C A231329 Conjecture: All terms are prime. %C A231329 a(5) > 10^5. %t A231329 Select[ Prime[ Range[1, 100000] ], PrimeQ[ (19^# + 4^#)/23 ]& ] %o A231329 (PARI) is(n)=ispseudoprime((19^n+4^n)/23) \\ _Charles R Greathouse IV_, Jun 13 2017 %Y A231329 Cf. A227049, A228558, A128075, A229612. %K A231329 hard,nonn,more %O A231329 1,1 %A A231329 _Robert Price_, Nov 07 2013