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 A216195 #20 Jan 14 2017 09:12:06
%S A216195 2,2,3,2,3,3,3,2,3,3,4,3,4,3,3,2,3,3,4,3,4,4,4,3,4,4,4,3,4,3,3,2,3,3,
%T A216195 4,3,4,4,4,3,4,4,5,4,5,4,4,3,4,4,5,4,5,4,4,3,4,4,4,3,4,3,3,2,3,3,4,3,
%U A216195 4,4,4,3,4,4,5,4,5,4,4,3,4,4,5,4,5,5,5,4,5,5,5,4,5,4,4,3,4,4,5
%N A216195 Abelian complexity function of the period-doubling sequence (A096268).
%D A216195 Michel Rigo, Formal Languages, Automata and Numeration Systems, 2 vols., Wiley, 2014. Mentions this sequence - see "List of Sequences" in Vol. 2.
%H A216195 Vincenzo Librandi, <a href="/A216195/b216195.txt">Table of n, a(n) for n = 1..10000</a>
%H A216195 Nathan Fox, <a href="/A216195/a216195.py.txt">Python code to generate sequence</a>
%F A216195 a(1) = 2; a(2n) = a(n); a(4n-1) = a(n) + 1; a(4n+1) = a(n) + 1.
%F A216195 a(n) = A007302(n) + 1.
%t A216195 a[n_]:=Count[BitXor[b1=IntegerDigits[n, 2]; b3=IntegerDigits[3*n, 2]; PadLeft[b1, Length[b3]], b3], 1]; Table[a[n] + 1, {n, 1, 100}] (* _Vincenzo Librandi_, Jan 13 2017 *)
%Y A216195 Cf. A007302, A096268.
%K A216195 nonn,easy
%O A216195 1,1
%A A216195 _Nathan Fox_, Mar 12 2013