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 A113401 #9 Feb 16 2025 08:32:59 %S A113401 1,1,1,1,2,1,2,2,2,4,4,8,4,4,4,8,8,8,8,16,8,16,16,16,32,16,16,16,32, %T A113401 32,32,32,32,32,32,64,64,128,64,64,64,64,64,64,64,128,128,128,128,128, %U A113401 128,256,128,128,128,256,256,256,256,512,256,256,256,256,256,256,512 %N A113401 Algebraic degree of cos(2*Pi/n) for constructible n-gons (A003401). %H A113401 Eric Weisstein's World of Mathematics, <a href="https://mathworld.wolfram.com/TrigonometryAngles.html">Trigonometry Angles</a> %Y A113401 Cf. A003401, A023022, A113402. %K A113401 nonn,easy,nice %O A113401 1,5 %A A113401 _Eric W. Weisstein_, Oct 28 2005