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 A011731 #13 Feb 17 2018 13:52:12 %S A011731 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,1,0,0,0,0,0,0,1,0,0,0,0,0,0,1,0,0, %T A011731 0,1,0,0,1,0,0,0,0,0,0,1,0,0,0,1,0,0,1,1,0,0,0,0,0,1,1,0,0,1,0,0,1,0, %U A011731 0,0,0,1,0,1,0,0,0,1,0,0,1 %N A011731 A binary m-sequence: expansion of reciprocal of x^18 + x^7 + 1 (mod 2, shifted by 17 initial 0's). %C A011731 Periodic with period of length 2^18 - 1 = 262143. - _M. F. Hasler_, Feb 17 2018 %D A011731 S. W. Golomb, Shift-Register Sequences, Holden-Day, San Francisco, 1967. %D A011731 H. D. Lueke, Korrelationssignale, Springer 1992, pp. 43-48. %D A011731 F. J. MacWilliams and N. J. A. Sloane, The Theory of Error-Correcting Codes, Elsevier/North Holland, 1978, p. 408. %H A011731 <a href="/index/Rec#order_262143">Index entries for linear recurrences with constant coefficients</a>, order 262143. %F A011731 G.f. = x^17/(x^18 + x^7 + 1), over GF(2). - _M. F. Hasler_, Feb 17 2018 %o A011731 (PARI) A=matrix(N=18,N,i,j,if(i>1,i==j+1,setsearch([7,N],j)>0))*Mod(1,2); a(n)=lift((A^(n-#A+1))[1,1]) \\ _M. F. Hasler_, Feb 17 2018 %Y A011731 Cf. A011655, A011656, ..., A011745 for other binary m-sequences, and A011746..A011751 for similar expansions over GF(2). %K A011731 nonn %O A011731 0,1 %A A011731 _N. J. A. Sloane_ %E A011731 Edited by _M. F. Hasler_, Feb 17 2018