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 A240503 #19 Jul 06 2024 13:52:30 %S A240503 4,8,72,396,4428,63152 %N A240503 Numbers k such that 5^k - 4^k - 3^k - 2^k - 1 is prime. %C A240503 a(7) > 70000. - _Giovanni Resta_, Apr 09 2014 %C A240503 a(7) > 110000. - _Michael S. Branicky_, Jul 06 2024 %e A240503 5^4-4^4-3^4-2^4-1 = 271 is prime. Thus, 4 is a term of this sequence. %o A240503 (PARI) for(n=1,7500,if(ispseudoprime(5^n-4^n-3^n-2^n-1),print(n))) %Y A240503 Cf. A000043, A240507. %K A240503 nonn,more %O A240503 1,1 %A A240503 _Derek Orr_, Apr 06 2014 %E A240503 a(6) from _Giovanni Resta_, Apr 09 2014