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 A133424 #9 Jul 10 2015 19:59:29 %S A133424 6,66,216,366,516,666,816,1116,2016,4866,5766,8616,9516,229866,286116, %T A133424 473616,737016,3230766,4438266,6260016,10637016,107662496,117661116, %U A133424 152291166,176254866,179900766,201566166,230949516 %N A133424 Analog of A060410 for the 5x+1 problem (cf. A133419). %C A133424 The 5x+1 map sends x to x/2 if x is even, x/3 if x is divisible by 3, otherwise 5x+1. %H A133424 N. J. A. Sloane, <a href="/A133424/b133424.txt">Table of n, a(n) for n=1..89</a> (from the web page of Tomás Oliveira e Silva) %H A133424 Tomás Oliveira e Silva, <a href="http://sweet.ua.pt/tos/3x+1.html">The px+1 problem</a> %H A133424 <a href="/index/3#3x1">Index entries for sequences related to 3x+1 (or Collatz) problem</a> %Y A133424 Cf. A133419, A133423, A133419, ... %K A133424 nonn %O A133424 1,1 %A A133424 _N. J. A. Sloane_, Nov 27 2007