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 A019849 #34 Aug 29 2025 11:45:16 %S A019849 6,4,2,7,8,7,6,0,9,6,8,6,5,3,9,3,2,6,3,2,2,6,4,3,4,0,9,9,0,7,2,6,3,4, %T A019849 3,2,9,0,7,5,5,9,8,8,4,2,0,5,6,8,1,7,9,0,3,2,4,9,7,7,2,5,4,6,7,1,1,1, %U A019849 2,8,3,6,2,4,0,9,5,8,6,3,9,7,1,0,4,8,8,2,2,7,7,1,7,5,9,4,3,5,1 %N A019849 Decimal expansion of sine of 40 degrees. %C A019849 This sequence is also the decimal expansion of cosine of 50 degrees. - _Mohammad K. Azarian_, Jun 29 2013 %C A019849 A sextic number with denominator 2. - _Charles R Greathouse IV_, Nov 05 2017 %H A019849 Ivan Panchenko, <a href="/A019849/b019849.txt">Table of n, a(n) for n = 0..1000</a> %H A019849 <a href="/index/Al#algebraic_06">Index entries for algebraic numbers, degree 6</a>. %F A019849 Equals cos(5*Pi/18) = 2F1(11/12,1/12;1/2;3/4) / 2. - _R. J. Mathar_, Oct 27 2008 %F A019849 Equals 2*A019829*A019879. - _R. J. Mathar_, Jan 17 2021 %F A019849 A root of 64*x^6 - 96*x^4 + 36*x^2 - 3. - _R. J. Mathar_, Aug 29 2025 %e A019849 0.642787609... %t A019849 RealDigits[ Sin[ 2Pi/9], 10, 111][[1]] (* _Robert G. Wilson v_, Feb 16 2011 *) %t A019849 RealDigits[Sin[40 Degree],10,120][[1]] (* _Harvey P. Dale_, Mar 27 2015 *) %o A019849 (PARI) sin(2/9*Pi) \\ _Charles R Greathouse IV_, Nov 05 2017 %o A019849 (PARI) polrootsreal(64*x^6-96*x^4+36*x^2-3)[5] \\ _Charles R Greathouse IV_, Feb 05 2025 %K A019849 nonn,cons,changed %O A019849 0,1 %A A019849 _N. J. A. Sloane_