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 A073449 #15 May 15 2021 03:54:14
%S A073449 6,4,2,0,9,2,6,1,5,9,3,4,3,3,0,7,0,3,0,0,6,4,1,9,9,8,6,5,9,4,2,6,5,6,
%T A073449 2,0,2,3,0,2,7,8,1,1,3,9,1,8,1,7,1,3,7,9,1,0,1,1,6,2,2,8,0,4,2,6,2,7,
%U A073449 6,8,5,6,8,3,9,1,6,4,6,7,2,1,9,8,4,8,2,9,1,9,7,6,0,1,9,6,8,0,4,6,5,8,1,4
%N A073449 Decimal expansion of cot(1).
%C A073449 By the Lindemann-Weierstrass theorem, this constant is transcendental. - _Charles R Greathouse IV_, May 13 2019
%H A073449 Mohammad K. Azarian, <a href="http://www.jstor.org/stable/30044897">Forty-Five Nested Equilateral Triangles and cosecant of 1 degree, Problem 813</a>, College Mathematics Journal, Vol. 36, No. 5, November 2005, pp. 413-414.
%H A073449 Mohammad K. Azarian, <a href="http://www.jstor.org/stable/27646393">Solution of Forty-Five Nested Equilateral Triangles and cosecant of 1 degree, Problem 813</a>, College Mathematics Journal, Vol. 37, No. 5, November 2006, pp. 394-395.
%H A073449 <a href="/index/Tra#transcendental">Index entries for transcendental numbers</a>
%F A073449 Equals Sum_{k>=0} (-1)^k * B(2*k) * 2^(2*k) / (2*k)!, where B(k) is the k-th Bernoulli number. - _Amiram Eldar_, May 15 2021
%e A073449 0.64209261593433070300641998659...
%t A073449 RealDigits[Cot[1], 10, 100][[1]] (* _Amiram Eldar_, May 15 2021 *)
%o A073449 (PARI) cotan(1)
%Y A073449 Cf. A049471 (tan(1)=1/A073449), A049469 (sin(1)), A049470 (cos(1)), A073447 (csc(1)), A073448 (sec(1)).
%K A073449 cons,nonn
%O A073449 0,1
%A A073449 _Rick L. Shepherd_, Aug 01 2002