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 A011657 #21 Feb 23 2018 03:34:11
%S A011657 0,0,1,1,1,0,1,0,0,1,1,1,0,1,0,0,1,1,1,0,1,0,0,1,1,1,0,1,0,0,1,1,1,0,
%T A011657 1,0,0,1,1,1,0,1,0,0,1,1,1,0,1,0,0,1,1,1,0,1,0,0,1,1,1,0,1,0,0,1,1,1,
%U A011657 0,1,0,0,1,1,1,0,1,0,0,1,1
%N A011657 A binary m-sequence: expansion of reciprocal of x^3 + x + 1 (mod 2, shifted by 2 initial 0's).
%C A011657 Period 7.
%D A011657 S. W. Golomb, Shift-Register Sequences, Holden-Day, San Francisco, 1967.
%D A011657 H. D. Lueke, Korrelationssignale, Springer 1992, pp. 43-48.
%D A011657 F. J. MacWilliams and N. J. A. Sloane, The Theory of Error-Correcting Codes, Elsevier/North Holland, 1978, p. 408.
%H A011657 <a href="/index/Rec#order_07">Index entries for linear recurrences with constant coefficients</a>, signature (0,0,0,0,0,0,1).
%F A011657 G.f.: (x^6 + x^3 + x + 1)/(1-x^7), a(n+7) = a(n). - _Ralf Stephan_, Aug 05 2013
%t A011657 Join[{0, 0}, Mod[CoefficientList[1/(x^3 + x + 1) + O[x]^80, x], 2]] (* _Jean-François Alcover_, Feb 23 2018 *)
%o A011657 (PARI) A011657(n)=bittest(92,n%7) \\ _M. F. Hasler_, Feb 17 2018
%Y A011657 Cf. A011655..A011751 for other binary m-sequences.
%K A011657 nonn,easy
%O A011657 0,1
%A A011657 _N. J. A. Sloane_