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 A387442 #10 Aug 31 2025 06:35:11 %S A387442 9,8,6,3,6,1,3,0,3,4,0,2,7,2,2,3,7,3,6,0,2,5,0,9,1,9,4,8,1,9,0,6,7,1, %T A387442 1,0,7,2,8,4,8,1,5,0,3,2,0,2,8,7,6,3,1,6,7,4,3,6,6,5,1,3,5,0,6,3,4,5, %U A387442 4,0,6,6,4,9,4,3,1,9,6,0,1,6,2,8,4,7,7,9,9,7,0,7,4,1,4,5,5,0,8,1,2,9,7,0,4,1,7,2,9,7,4,9,8,1,7,2,4,5 %N A387442 Decimal expansion of cos(Pi/19). %H A387442 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 A387442 <a href="/index/Al#algebraic_09">Index entries for algebraic numbers, degree 9</a> %F A387442 Equals sin(17*Pi/38). %F A387442 Largest root of 512*x^9 -256*x^8 -1024*x^7 +448*x^6 +672*x^5 -240*x^4 -160*x^3 +40*x^2 +10*x -1 =0. %e A387442 0.98636130340272237360... %Y A387442 Cf. A019686. %K A387442 nonn,cons,new %O A387442 0,1 %A A387442 _R. J. Mathar_, Aug 29 2025