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 A019875 #22 Aug 21 2023 11:16:54 %S A019875 9,1,3,5,4,5,4,5,7,6,4,2,6,0,0,8,9,5,5,0,2,1,2,7,5,7,1,9,8,5,3,1,7,1, %T A019875 7,7,9,4,0,8,1,0,4,5,9,3,7,7,4,7,4,5,4,5,0,6,0,9,9,9,7,8,8,0,6,5,1,1, %U A019875 4,8,8,2,1,0,2,6,3,1,2,7,1,6,8,1,7,8,4,0,0,0,8,9,3,2,9,9,9,9,4 %N A019875 Decimal expansion of sine of 66 degrees. %C A019875 A quartic number with denominator 2. - _Charles R Greathouse IV_, Aug 27 2017 %H A019875 Ivan Panchenko, <a href="/A019875/b019875.txt">Table of n, a(n) for n = 0..1000</a> %H A019875 Wikipedia, <a href="http://en.wikipedia.org/wiki/Exact_trigonometric_constants">Exact trigonometric constants</a> %H A019875 <a href="/index/Al#algebraic_04">Index entries for algebraic numbers, degree 4</a> %F A019875 Equals cos(2*Pi/15) = 2*A019887^2 - 1 = 1 - 2*A019821^2. - _R. J. Mathar_, Jun 18 2006 %F A019875 Equals 2*A019842*A019866. - _R. J. Mathar_, Jan 17 2021 %e A019875 0.913545457... %t A019875 RealDigits[N[Cos[2*Pi/15], 110]][[1]] (* _Wesley Ivan Hurt_, Dec 27 2021 *) %o A019875 (PARI) cos(2*Pi/15) \\ _Charles R Greathouse IV_, Aug 27 2017 %Y A019875 Cf. A019821, A019842, A019866, A019887. %K A019875 nonn,cons %O A019875 0,1 %A A019875 _N. J. A. Sloane_