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 A199817 #11 Mar 30 2012 18:38:26
%S A199817 11,35,113,341
%N A199817 Odd numbers producing 10 even numbers in the Collatz iteration.
%t A199817 Collatz[n_]:=NestWhileList[If[EvenQ[#],#/2,3 #+1]&,n,#>1&];t={};Do[If[Length[Select[Collatz[n],EvenQ]] == 10,AppendTo[t,n]],{n,1,100000,2}];t
%Y A199817 Cf. A131450.
%Y A199817 Cf. A199636 (row 10).
%K A199817 nonn
%O A199817 1,1
%A A199817 _Vincenzo Librandi_, Nov 12 2011