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 A182006 #15 Feb 13 2013 23:58:28
%S A182006 2,3,2,2,3,2,3,2,2,2,3,2,2,2,2,3,3,3,2,3,2,2,3,2,2,2,4,2,2,2,2,2,2,3,
%T A182006 2,2,2,3,2,2,2,3,2,2,2,3,3,2,2,2,3,2,2,2,2,2,3,3,3,2,2,2,2,3,2,2,2,2,
%U A182006 2,2,2,3,2,2,2,3,2,2,2,2,3,2,3,3,2,2,3,2,2,2,2,3,2,2,2,3,2,3
%N A182006 Lengths of periods of iterations described in A182005 for terms of A182005.
%C A182006 Period of length 4 occurs for terms of A182005 equaled 91, 405, 659, 873, 1335, 1723, 1751,... For example, for 91 we have period {52, 50, 60, 54}. Up to now, periods of lengths 5 or 6 were not found.
%t A182006 period[seq_] := (If[Last[#1] == {} || Length[#1] == Length[seq] -1, 0, Length[#1]]&)[NestWhileList[Rest, Rest[seq], #1 != Take[seq, Length[#1]]&, 1]]; {A182005, A182006} = Transpose[Select[Table[{n, period[Take[Module[{p}, Flatten[{p=Apply[Plus, IntegerDigits[2^#, 3]], Table[p=Apply[Plus, IntegerDigits[2^#+p,3]], {40}]}&[n]]], -20]]}, {n,1,500}], #[[2]] =!= 1&]]
%Y A182006 Cf. A182005.
%K A182006 nonn,base
%O A182006 1,1
%A A182006 _Vladimir Shevelev_ and _Peter J. C. Moses_, Apr 06 2012