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 A217743 #16 Mar 25 2013 14:25:55
%S A217743 1,1,1,1,2,1,2,1,3,2,3,1,3,2,0,1,4,3,3,2,2,3,1,1,4,3,-6,2,4,0,-6,1,5,
%T A217743 4,2,3,3,3,2,2,-5,2,4,3,5,1,-5,1,4,4,4,3,3,-6,-6,2,5,4,3,0,2,-6,-8,1,
%U A217743 5,5,3,4,4,2,-4,3,-5,3,2,3,5,2,2,2,3,-5,-5
%N A217743 Excess of number of odds in the form 4k+1 over number of odds in the form 4k+3 in Collatz trajectory of n.
%H A217743 T. D. Noe, <a href="/A217743/b217743.txt">Table of n, a(n) for n = 1..10000</a>
%t A217743 Collatz[n_] := NestWhileList[If[EvenQ[#], #/2, 3*# + 1] &, n, # > 1 &]; Table[Length[Select[Collatz[n], Mod[#, 4] == 1 &]] - Length[Select[Collatz[n], Mod[#, 4] == 3 &]], {n,60}]
%t A217743 Table[m4=Mod[NestWhileList[If[EvenQ[#],#/2,3*#+1]&,n,#>1&],4];Count[m4, 1]-Count[m4, 3], {n, 60}] (* _Zak Seidov_, Mar 23 2013 *)
%Y A217743 Cf. A070165, A192719.
%Y A217743 Cf. A217744 (n having equal numbers of 4k+1 and 4k+3 terms).
%K A217743 sign
%O A217743 1,5
%A A217743 _Jayanta Basu_, Mar 23 2013