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 A019948 #13 Aug 29 2025 12:37:21 %S A019948 1,1,9,1,7,5,3,5,9,2,5,9,4,2,0,9,9,5,8,7,0,5,3,0,8,0,7,1,8,6,0,4,1,9, %T A019948 3,3,6,9,3,0,7,0,0,4,0,7,7,0,8,5,4,3,8,5,3,6,5,4,8,3,0,0,0,6,9,0,3,4, %U A019948 1,2,1,4,5,8,9,0,5,5,1,7,7,2,7,5,8,1,0,9,3,9,4,2,7,3,7,7,7,7,3 %N A019948 Decimal expansion of tangent of 50 degrees. %C A019948 Also the decimal expansion of cotangent of 40 degrees. - _Ivan Panchenko_, Sep 01 2014 %H A019948 Ivan Panchenko, <a href="/A019948/b019948.txt">Table of n, a(n) for n = 1..1000</a> %H A019948 <a href="/index/Al#algebraic_06">Index entries for algebraic numbers, degree 6</a> %F A019948 A root of 3*x^6 -27*x^4 +33*x^2 -1 =0 (others A019968, A019908). - _R. J. Mathar_, Aug 29 2025 %e A019948 1.19175359259420995870530807186041933693070040770854385365483... %t A019948 RealDigits[Tan[5*Pi/18], 10, 100][[1]] (* _G. C. Greubel_, Nov 23 2018 *) %o A019948 (PARI) default(realprecision, 100); tan(5*Pi/18) \\ _G. C. Greubel_, Nov 23 2018 %o A019948 (Magma) SetDefaultRealField(RealField(100)); R:= RealField(); Tan(5*Pi(R)/18); // _G. C. Greubel_, Nov 23 2018 %o A019948 (Sage) numerical_approx(tan(5*pi/18), digits=100) # _G. C. Greubel_, Nov 23 2018 %Y A019948 Cf. A019859 (sine of 50 degrees). %K A019948 nonn,cons,changed %O A019948 1,3 %A A019948 _N. J. A. Sloane_