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 A074249 #35 Sep 11 2022 12:48:41
%S A074249 3,3,19,5,2801,43,4733,1201,1063,2801,293459,181,16148168401,4733,
%T A074249 159871,169553,2767631689,117307,4534166740403,4021,11898664849,
%U A074249 10746341,31479823396757,1201,31280679788951,16148168401,2583253
%N A074249 a(n) = largest prime factor of 7^n-1.
%H A074249 <a href="/A074249/b074249.txt">Table of n, a(n) for n = 1..388</a>
%F A074249 a(n) = A006530(A024075(n)). - _Michel Marcus_, Dec 16 2017
%t A074249 Join[{1}, Table[FactorInteger[7^n - 1] [[-1, 1]], {n, 30}]] (* _Vincenzo Librandi_, Aug 23 2012 *)
%o A074249 (PARI) a(n) = vecmax(factor(7^n-1)[,1]); \\ _Michel Marcus_, Dec 16 2017
%Y A074249 Cf. A006530, A024075, A057954, A059889, A085032.
%K A074249 nonn
%O A074249 1,1
%A A074249 _N. J. A. Sloane_, Sep 26 2002
%E A074249 More terms from _Benoit Cloitre_, Sep 29 2002
%E A074249 Terms to a(80) in b-file from _Vincenzo Librandi_, Aug 23 2013
%E A074249 a(81)-a(378) in b-file from _Amiram Eldar_, Feb 02 2020
%E A074249 a(0) removed and a(379)-a(388) in b-file added by _Max Alekseyev_, Apr 25 2022, Sep 11 2022