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 A226615 #5 Aug 05 2013 05:35:00 %S A226615 2,3,6,4,7,5,20,11,12,28,6,38,44,48,72,18,106,29,75,7,37,14,10,42,72, %T A226615 66,10,68,38,58,72,8,43,110,22,33,68,29,42,71,13,46,121,28,182,200,47, %U A226615 9,21,60,108,28,156,19,22,85,79,151,62,56,71,60,78,226,104,192 %N A226615 Length of the Collatz-like 3x+k cycle associated with A226614(n). %H A226615 Geoffrey H. Morley, <a href="/A226615/b226615.txt">Table of n, a(n) for n = 1..10000</a> %H A226615 <a href="/index/3#3x1">Index entries for sequences related to 3x+1 (or Collatz) problem</a> %F A226615 a(n) = A226609(A226612(floor(A226614(n)/3)+1)). %F A226615 For n>227, this formula requires terms beyond A226609(10000). %o A226615 (PARI) See A226614. %K A226615 nonn %O A226615 1,1 %A A226615 _Geoffrey H. Morley_, Aug 02 2013