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 A387441 #9 Aug 31 2025 06:34:48 %S A387441 9,7,0,9,4,1,8,1,7,4,2,6,0,5,2,0,2,7,1,5,6,9,8,2,2,7,6,2,9,3,7,8,9,2, %T A387441 2,7,2,4,9,8,6,5,1,0,5,7,3,9,0,0,3,5,8,8,5,8,7,6,4,4,5,2,6,4,7,7,0,4, %U A387441 1,7,0,8,7,6,0,0,0,6,6,7,6,9,3,2,5,7,4,6,0,6,4,0,8,3,8,4,2,6,1,5,5,4,4,3,8,2,0,5,4,9,7,5,0,0,9,9,1,9 %N A387441 Decimal expansion of cos(Pi/13). %H A387441 R. J. Mathar, <a href="https://vixra.org/abs/2210.0026">Reduction formulas of the cosine of integer fractions of pi</a>, (2008) vixra:2210.0026 %H A387441 <a href="/index/Al#algebraic_06">Index entries for algebraic numbers, degree 6</a> %F A387441 Largest of the 6 real-valued roots of 64*x^6 -32*x^5 -80*x^4 +32*x^3 +24*x^2 -6*x -1 = 0. %F A387441 Equals sin(11/26*Pi). %e A387441 0.97094181742605202716... %Y A387441 Cf. A019680. %K A387441 nonn,cons,new %O A387441 0,1 %A A387441 _R. J. Mathar_, Aug 29 2025