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 A128453 #17 Apr 18 2019 02:55:18
%S A128453 6,12,38,2540
%N A128453 Numbers k such that absolute value of 13^k - k^13 is prime.
%C A128453 a(5) > 10^5. - _Robert Price_, Apr 17 2019
%t A128453 Do[If[PrimeQ[13^n - n^13], Print[n]], {n, 10^4}] (* _Ryan Propper_, Jul 01 2007 *)
%o A128453 (PARI) is(n)=ispseudoprime(abs(13^n-n^13)) \\ _Charles R Greathouse IV_, Feb 17 2017
%K A128453 hard,more,nonn,less
%O A128453 1,1
%A A128453 _Alexander Adamchuk_, Mar 03 2007
%E A128453 a(4) from _Ryan Propper_, Jul 01 2007