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 A375191 #15 Feb 05 2025 10:07:50 %S A375191 1,7,0,2,8,4,3,6,1,9,4,4,4,6,2,5,0,0,4,5,2,4,0,6,5,1,7,3,3,2,4,4,2,4, %T A375191 4,1,5,9,7,8,6,4,9,9,9,3,0,6,0,9,1,4,0,7,0,4,8,8,9,6,7,0,3,0,5,3,5,9, %U A375191 7,6,5,3,4,5,1,3,2,9,1,0,4,8,1,1,1,4,5,7,0,2 %N A375191 Decimal expansion of the apothem (inradius) of a regular 11-gon with unit side length. %H A375191 Paolo Xausa, <a href="/A375191/b375191.txt">Table of n, a(n) for n = 1..10000</a> %H A375191 Eric Weisstein's World of Mathematics, <a href="https://mathworld.wolfram.com/RegularPolygon.html">Regular Polygon</a>. %H A375191 Wikipedia, <a href="https://en.wikipedia.org/wiki/Apothem">Apothem</a>. %H A375191 <a href="/index/Al#algebraic_10">Index entries for algebraic numbers, degree 10</a>. %F A375191 Equals cot(Pi/11)/2. %F A375191 Equals 1/(2*tan(Pi/11)). %F A375191 Equals A375190*cos(Pi/11). %F A375191 Equals A375190 - A375192. %e A375191 1.702843619444625004524065173324424415978649993... %t A375191 First[RealDigits[Cot[Pi/11]/2, 10, 100]] %o A375191 (PARI) .5/tan(Pi/11) \\ _Charles R Greathouse IV_, Feb 05 2025 %Y A375191 Cf. A375190 (circumradius), A375192 (sagitta), A256854 (area). %Y A375191 Cf. apothem of other polygons with unit side length: A020769 (triangle), A020761 (square), A375067 (pentagon), A010527 (hexagon), A374971 (heptagon), A174968 (octagon), A375152 (9-gon), A179452 (10-gon), A375193 (12-gon). %K A375191 nonn,cons,easy %O A375191 1,2 %A A375191 _Paolo Xausa_, Aug 04 2024