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 A071004 #22 Oct 15 2018 00:03:01 %S A071004 1,0,0,1,1,0,0,1,0,1,0,1,1,1,0,0,1,0,1,0,1,0,0,0,1,1,0,0,0,0,1,0,0,0, %T A071004 0,1,1,0,1,1,0,0,0,0,0,1,1,0,0,1,0,1,1,1,0,1,0,1,1,0,0,0,1,1,0,0,1,1, %U A071004 1,1,1,0,1,0,0,0,1,0,1,1,1,0,0,1,1,0,1,1,1,1,0,1,1,0,0,0,0,1,1,0,0,0,0,0,0 %N A071004 Binary expansion of AGM(1,sqrt(2)) where AGM(x,y) denote the arithmetic-geometric mean of (x,y). %H A071004 G. C. Greubel, <a href="/A071004/b071004.txt">Table of n, a(n) for n = 1..10000</a> %t A071004 RealDigits[ArithmeticGeometricMean[1,Sqrt[2]],2,120][[1]] (* _Harvey P. Dale_, Mar 30 2015 *) %o A071004 (PARI) a(n)=agm(sqrt(2),1)*2^(n-1)\1%2 \\ _Charles R Greathouse IV_, Mar 03 2016 %Y A071004 Cf. A053004. %K A071004 base,cons,nonn %O A071004 1,1 %A A071004 _Benoit Cloitre_, Aug 17 2002