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 A033137 #29 Dec 14 2023 05:44:00
%S A033137 1,11,110,1101,11011,110110,1101101,11011011,110110110,1101101101,
%T A033137 11011011011,110110110110,1101101101101,11011011011011,
%U A033137 110110110110110,1101101101101101
%N A033137 Decimal expansion of a(n) is given by the first n terms of the periodic sequence with initial period 1,1,0.
%H A033137 Vincenzo Librandi, <a href="/A033137/b033137.txt">Table of n, a(n) for n = 1..1000</a>
%H A033137 <a href="/index/Rec#order_04">Index entries for linear recurrences with constant coefficients</a>, signature (10,0,1,-10).
%F A033137 G.f.: x*(1+x) / ( (x-1)*(10*x-1)*(1+x+x^2) ). - _R. J. Mathar_, Jan 08 2011
%t A033137 Table[FromDigits[PadRight[{},n,{1,1,0}]],{n,20}] (* _Harvey P. Dale_, Aug 13 2014 *)
%t A033137 CoefficientList[Series[(1 + x)/((x - 1) (10 x - 1) (1 + x + x^2)), {x, 0, 20}], x] (* _Vincenzo Librandi_, Aug 14 2014 *)
%K A033137 nonn,base,easy
%O A033137 1,2
%A A033137 _Clark Kimberling_