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 A213204 #10 Mar 01 2013 15:04:32
%S A213204 1,1,6,1,3,4,13,1,14,2,9,2,4,9,12,1,5,8,11,1,3,5,8,1,11,2,103,4,6,9,
%T A213204 98,1,11,3,6,3,5,6,18,1,98,2,11,2,4,6,93,1,6,5,8,1,3,96,99,1,10,2,12,
%U A213204 5,7,92,94,1,6,4,7,1,3,4,88,1,98,2,8,2,4,11,14
%N A213204 Number of terms of the Collatz (3x+1) trajectory of n that are greater than or equal to n.
%H A213204 T. D. Noe, <a href="/A213204/b213204.txt">Table of n, a(n) for n = 1..10000</a>
%F A213204 a(n) = A222597(n) - 1.
%e A213204 For n=3, the Collatz trajectory is 3, 10, 5, 16, 8, 4, 2, 1 and hence a(3)=6.
%t A213204 Collatz[n_] := NestWhileList[If[EvenQ[#], #/2, 3 # + 1] &, n, # > 1 &]; Table[Length[Select[Collatz[n], # >= n &]], {n, 100}]
%Y A213204 Cf. A076228, A222597.
%K A213204 nonn
%O A213204 1,3
%A A213204 _Jayanta Basu_, Mar 01 2013