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 A366720 #15 Jan 04 2024 15:46:40
%S A366720 2,13,29,19,233,19141,20593,13063,260753,1801,85403261,57154490053,
%T A366720 2227777,222379,13156924369,35671,1200913648289,66900193189411,
%U A366720 122138321401,905265296671,67657441,1885339,68368660537,49489630860836437,592734049,438472201
%N A366720 Largest prime factor of 12^n+1.
%H A366720 Max Alekseyev, <a href="/A366720/b366720.txt">Table of n, a(n) for n = 0..306</a>
%F A366720 a(n) = A006530(A178248(n)). - _Paul F. Marrero Romero_, Dec 07 2023
%t A366720 Table[FactorInteger[12^n + 1][[-1, 1]], {n, 0, 20}]
%Y A366720 Cf. A178248, A006530, A002587, A074476, A274903, A074478, A274904, A227575, A274905, A002592, A003021, A062308, A002590, A366712, A366713, A366714, A366715, A366716, A366717, A366718, A366719, A324941.
%K A366720 nonn
%O A366720 0,1
%A A366720 _Sean A. Irvine_, Oct 17 2023