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 A019978 #15 Aug 31 2025 12:48:33 %S A019978 5,6,7,1,2,8,1,8,1,9,6,1,7,7,0,9,5,3,0,9,9,4,4,1,8,4,3,9,8,6,3,9,6,4, %T A019978 4,2,1,6,2,5,3,7,8,2,6,0,6,8,9,7,5,0,3,0,3,2,1,5,9,0,9,9,8,8,8,7,5,2, %U A019978 4,3,4,1,6,6,8,0,9,4,4,9,9,4,1,7,9,8,5,9,8,2,6,9,8,1,7,2,8,1,7 %N A019978 Decimal expansion of tangent of 80 degrees. %H A019978 Ivan Panchenko, <a href="/A019978/b019978.txt">Table of n, a(n) for n = 1..1000</a> %H A019978 <a href="/index/Al#algebraic_06">Index entries for algebraic numbers, degree 6</a> %F A019978 Largest positive of the 6 real-valued roots of x^6-33*x^4+27*x^2-3=0. - _R. J. Mathar_, Aug 31 2025 %F A019978 Equals A019889/A019819. - _R. J. Mathar_, Aug 31 2025 %e A019978 tan(4*Pi/9) = 5.67128183... %t A019978 RealDigits[Tan[80 Degree],10,120][[1]] (* _Harvey P. Dale_, Jan 04 2013 *) %K A019978 nonn,cons,changed %O A019978 1,1 %A A019978 _N. J. A. Sloane_