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 A109387 #14 Mar 12 2023 08:48:23
%S A109387 1,4,10,52,112,212,346,406,512,13904,76610,89746,114892
%N A109387 Numbers k such that 3^k - k^3 is prime.
%C A109387 Terms <= 512 correspond to certified primes. Next term after 13904 is greater than 20000.
%e A109387 4 is a term because 3^4 - 4^3 = 17 is prime.
%e A109387 3^10 - 10^3 = 58049 is prime, hence 10 is a term.
%t A109387 Do[If[PrimeQ[3^n - n^3], Print[n]], {n, 1, 20000}]
%o A109387 (PARI) is(n)=isprime(3^n-n^3) \\ _Charles R Greathouse IV_, Feb 17 2017
%K A109387 hard,more,nonn
%O A109387 1,2
%A A109387 _Ryan Propper_, Jun 26 2005
%E A109387 Two more terms from _Donovan Johnson_, Feb 26 2008
%E A109387 a(13) from Norbert Schneider submitted by _Robert Price_, Mar 16 2019