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 A161018 #15 Jun 27 2023 05:11:12
%S A161018 1,1,1,5,7,0,6,2,7,8,3,3,8,0,0,5,8,3,7,2,6,5,0,4,8,0,0,2,4,9,8,2,9,4,
%T A161018 6,4,5,0,2,5,4,9,2,3,4,1,2,7,7,4,0,0,7,3,1,1,1,7,6,8,4,7,2,5,0,7,6,3,
%U A161018 7,2,3,9,4,8,2,2,3,5,8,5,2,3,5,7,9,4,1,4,5,7,4,1,1,0,6,6,1,3,2,8,4,0,7,8,6
%N A161018 Decimal expansion of tan(1/9).
%C A161018 By the Lindemann-Weierstrass theorem, this constant is transcendental. - _Charles R Greathouse IV_, May 13 2019
%H A161018 Harry J. Smith, <a href="/A161018/b161018.txt">Table of n, a(n) for n = 0..20000</a>
%H A161018 <a href="/index/Tra#transcendental">Index entries for transcendental numbers</a>.
%e A161018 0.111570627833800583726504800249829464502549234127740073111768472507637...
%t A161018 RealDigits[Tan[1/9], 10, 120][[1]] (* _Amiram Eldar_, Jun 27 2023 *)
%o A161018 (PARI) default(realprecision, 20080); x=10*tan(1/9); for (n=0, 20000, d=floor(x); x=(x-d)*10; write("b161018.txt", n, " ", d));
%Y A161018 Cf. A019432 (continued fraction).
%K A161018 cons,nonn
%O A161018 0,4
%A A161018 _Harry J. Smith_, Jun 14 2009