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 A364453 #31 Aug 24 2024 15:43:22
%S A364453 2,4,64,124,228,10978,73738,66346
%N A364453 Smallest k such that 5^(5^n) - k is prime.
%C A364453 This is to 5 as A058220 is to 2 and A140331 is to 3.
%C A364453 a(7) > 5487.
%F A364453 a(n) = A064722(A137841(n)).
%e A364453 a(2) = 64 because 5^(5^2) - 64 = 298023223876953061 is prime.
%t A364453 lst={};Do[Do[p=5^(5^n)-k;If[PrimeQ[p],AppendTo[lst,k];Break[]],{k,2,11!}],{n,7}];lst
%t A364453 Table[k=1;Monitor[Parallelize[While[True,If[PrimeQ[5^(5^n)-k],Break[]];k++];k],k],{n,1,7}]
%t A364453 y[n_] := Module[{x = 5^(5^n)}, x - NextPrime[x, -1]]; Array[y, 7]
%o A364453 (PARI) a(n) = my(x = 5^(5^n)); x - precprime(x);
%Y A364453 Cf. A064722, A137841.
%Y A364453 Cf. A058220, A140331, A364452, A364454.
%K A364453 more,nonn
%O A364453 0,1
%A A364453 _J.W.L. (Jan) Eerland_, Jul 25 2023
%E A364453 a(0) prepended and a(7) from _Michael S. Branicky_, Aug 24 2024