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 A033492 #30 Jun 15 2019 10:26:11 %S A033492 1,2,8,9,17,20,21,24,112,113,116,119,122,125,128,131,144,145,171,179, %T A033492 182,183,209,217,238,262,268,276,279,282,308,311,324,340,351,354,375, %U A033492 383,386,443,449,470,509,525,528,531,557,560,563,584,597,613,665,686 %N A033492 Record number of steps to reach 1 in '3x+1' problem, corresponding to starting values in A006877 (same as A006878 except here we start counting at 1 instead of 0). %C A033492 Both the 3x+1 steps and the halving steps are counted. %D A033492 R. E. Maeder, Programming in Mathematica, 3rd Edition, Addison-Wesley, pages 251-252. %H A033492 T. D. Noe, <a href="/A033492/b033492.txt">Table of n, a(n) for n=1..130</a> (from Eric Roosendaal's data) %H A033492 Eric Roosendaal, <a href="http://www.ericr.nl/wondrous/delrecs.html">3x+1 Delay Records</a> %H A033492 <a href="/index/3#3x1">Index entries for sequences related to 3x+1 (or Collatz) problem</a> %Y A033492 Equal to A006878 + 1. Cf. A006884, A006885, A033492. %K A033492 nonn %O A033492 1,2 %A A033492 _Jeff Burch_ %E A033492 Corrected and extended by Lee Corbin (lcorbin(AT)tsoft.com) %E A033492 More terms from Larry Reeves (larryr(AT)acm.org), Apr 27 2001