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 A179623 #20 Feb 16 2025 08:33:12 %S A179623 3711,11134,5567,16702,8351,25054,12527,37582,18791,56374,28187,84562, %T A179623 42281,126844,63422,31711,95134,47567,142702,71351,214054,107027, %U A179623 321082,160541,481624,240812,120406,60203,180610,90305,270916,135458,67729 %N A179623 Collatz trajectory starting at 3711. %H A179623 G. C. Greubel, <a href="/A179623/b179623.txt">Table of n, a(n) for n = 1..238</a> %H A179623 Eric Weisstein's World of Mathematics, <a href="https://mathworld.wolfram.com/CollatzProblem.html">Collatz Problem</a> %H A179623 Wikipedia, <a href="http://en.wikipedia.org/wiki/Collatz_conjecture">Collatz conjecture</a> %t A179623 f[n_] := If[ OddQ@n, 3 n + 1, n/2]; NestWhileList[f, 3711, # > 1 &] (* modified by _Robert G. Wilson v_, Aug 23 2010 *) %Y A179623 Cf. A161021. %K A179623 nonn,fini,full,easy %O A179623 1,1 %A A179623 _Vladimir Joseph Stephan Orlovsky_, Jul 20 2010