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 A019982 #20 Sep 06 2025 08:06:42 %S A019982 9,5,1,4,3,6,4,4,5,4,2,2,2,5,8,4,9,2,9,6,8,3,9,7,1,4,5,4,9,4,5,6,8,2, %T A019982 4,6,6,6,4,8,7,6,8,1,4,5,1,5,0,6,5,9,2,2,7,3,1,1,2,6,4,8,9,1,4,6,9,8, %U A019982 1,0,6,9,9,9,9,7,1,6,7,4,9,4,2,7,3,5,4,2,3,1,2,1,7,3,9,3,7,8,2 %N A019982 Decimal expansion of tangent of 84 degrees. %C A019982 Also the decimal expansion of cotangent of 6 degrees. - _Ivan Panchenko_, Sep 01 2014 %H A019982 Ivan Panchenko, <a href="/A019982/b019982.txt">Table of n, a(n) for n = 1..1000</a> %H A019982 Wikipedia, <a href="http://en.wikipedia.org/wiki/Exact_trigonometric_constants">Exact trigonometric constants</a>. %H A019982 <a href="/index/Al#algebraic_08">Index entries for algebraic numbers, degree 8</a> %F A019982 From _Amiram Eldar_, Apr 07 2022: (Start) %F A019982 Equals tan(78 degrees) + tan(72 degrees) + tan(60 degrees). %F A019982 Equals sqrt(23 + 10*sqrt(5) + 2*sqrt(3*(85 + 38*sqrt(5)))). %F A019982 The 4th positive and largest root of x^8 - 92*x^6 + 134*x^4 - 28*x^2 + 1 = 0. (End) %F A019982 Equals A019893/A019815. - _R. J. Mathar_, Sep 06 2025 %e A019982 tan(7*Pi/15) = 9.5143644... %t A019982 RealDigits[Tan[7*Pi/15], 10, 100][[1]] (* _Amiram Eldar_, Apr 07 2022 *) %Y A019982 Cf. A019970, A019976. %K A019982 nonn,cons,changed %O A019982 1,1 %A A019982 _N. J. A. Sloane_