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 A020991 #29 Jul 05 2025 17:11:56 %S A020991 0,3,6,15,26,27,30,63,106,107,110,111,122,123,126,255,426,427,430,431, %T A020991 442,443,446,447,490,491,494,495,506,507,510,1023,1706,1707,1710,1711, %U A020991 1722,1723,1726,1727,1770,1771,1774,1775,1786,1787,1790,1791,1962,1963 %N A020991 Largest value of k for which Golay-Rudin-Shapiro sequence A020986(k) = n. %H A020991 Seiichi Manyama, <a href="/A020991/b020991.txt">Table of n, a(n) for n = 1..10000</a> %H A020991 J. Brillhart and P. Morton, <a href="http://www.maa.org/programs/maa-awards/writing-awards/a-case-study-in-mathematical-research-the-golay-rudin-shapiro-sequence">A case study in mathematical research: the Golay-Rudin-Shapiro sequence</a>, Amer. Math. Monthly, 103 (1996) 854-869. %H A020991 Eric Weisstein's World of Mathematics, <a href="https://mathworld.wolfram.com/Rudin-ShapiroSequence.html">Rudin-Shapiro Sequence</a> %F A020991 a(2^n) = 2^(2n) - 1. - _Seiichi Manyama_, Apr 23 2017 %Y A020991 Cf. A020986, A212591. %K A020991 nonn %O A020991 1,2 %A A020991 _N. J. A. Sloane_ %E A020991 More terms from _Robert G. Wilson v_; further extended by _David W. Wilson_, Jun 1997