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 A364454 #26 Aug 23 2024 21:09:18
%S A364454 1,7,35,587,629,1819,106843
%N A364454 Smallest k such that 6^(6^n) - k is prime.
%C A364454 This is to 6 as A058220 is to 2 and A140331 is to 3.
%e A364454 a(2) = 35 because 6^(6^2) - 35 = 10314424798490535546171949021 is prime.
%t A364454 lst={};Do[Do[p=6^(6^n)-k;If[PrimeQ[p],AppendTo[lst,k];Break[]],{k,2,11!}],{n,7}];lst
%t A364454 Table[k=1;Monitor[Parallelize[While[True,If[PrimeQ[6^(6^n)-k],Break[]];k++];k],k],{n,1,7}]
%t A364454 y[n_] := Module[{x = 6^(6^n)}, x - NextPrime[x, -1]]; Array[y, 7]
%o A364454 (PARI) a(n) = my(x = 6^(6^n)); x - precprime(x);
%Y A364454 Cf. A058220, A140331, A364452, A364453.
%K A364454 more,nonn
%O A364454 0,2
%A A364454 _J.W.L. (Jan) Eerland_, Jul 25 2023
%E A364454 a(6) from _Michael S. Branicky_, Aug 23 2024
%E A364454 a(0)=1 prepended by _Alois P. Heinz_, Aug 23 2024