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 A019907 #25 Aug 31 2025 12:41:14 %S A019907 1,5,8,3,8,4,4,4,0,3,2,4,5,3,6,2,9,3,8,3,8,8,8,3,0,9,2,6,9,4,3,6,6,4, %T A019907 1,1,4,3,3,9,1,6,2,1,6,0,7,3,7,3,3,2,9,7,2,3,1,7,4,0,9,9,5,0,3,5,6,5, %U A019907 7,6,3,7,1,4,2,7,1,3,9,8,0,9,5,9,8,2,0,6,8,6,7,1,1,6,7,6,8,3,9 %N A019907 Decimal expansion of tangent of 9 degrees. %C A019907 Also the decimal expansion of cotangent of 81 degrees. - _Mohammad K. Azarian_, Jun 30 2013 %H A019907 Ivan Panchenko, <a href="/A019907/b019907.txt">Table of n, a(n) for n = 0..1000</a> %H A019907 Wikipedia, <a href="http://en.wikipedia.org/wiki/Exact_trigonometric_constants">Exact trigonometric constants</a> %H A019907 <a href="/index/Al#algebraic_08">Index entries for algebraic numbers, degree 8</a> %F A019907 Equals tan(Pi/20) = A019818/A019890. - _R. J. Mathar_, Aug 29 2025 %F A019907 Smallest positive of the 8 real-valued roots of x^8-44*x^6+166*x^4-44*x^2+1=0. (Others A019925, A019961, A019979). - _R. J. Mathar_, Aug 31 2025 %t A019907 RealDigits[Tan[9 Degree],10,120][[1]] (* _Harvey P. Dale_, Aug 23 2020 *) %K A019907 nonn,cons,changed %O A019907 0,2 %A A019907 _N. J. A. Sloane_