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 A335864 #11 Nov 17 2020 21:36:32
%S A335864 7,5,8,8,8,6,8,4,2,2,9,6,9,4,1,3,0,4,8,4,9,3,8,2,2,8,4,3,7,5,8,5,9,5,
%T A335864 4,6,0,6,9,2,5,2,6,2,7,8,4,4,8,5,4,6,1,2,5,6,6,6,0,5,9,2,5,6,4,2,9,6,
%U A335864 0,5,6,3,4,2,2,5,8,6,9,9,1,8,6,0,1,0,0,9,1,8,7,1,1,7,9,1,0
%N A335864 Decimal expansion of the negative of the zero x3 of the cubic polynomial x^3 - 2*x^2 - 10*x - 6.
%C A335864 For details and links see A335862.
%H A335864 Wolfdieter Lang, <a href="https://www.itp.kit.edu/~wl/EISpub/A333852.pdf">A list of representative simple difference sets of the Singer type for small orders m</a>, Karlsruher Institut für Technologie (Karlsruhe, Germany 2020).
%F A335864 -x3 = (1/3)*(2 - (1/2)*(1 + sqrt(3)*i)*(179 + 3*sqrt(3)*sqrt(269)*i)^(1/3) - (1/2)*(1 - sqrt(3)*i)*(179 - 3*sqrt(3)*sqrt(269)*i)^(1/3)), where i is the imaginary unit.
%e A335864 -x3 = 0.758886842296941304849382284375859546...
%p A335864 evalf((f-> (sqrt(34)*(cos(f)-sin(f)*sqrt(3))-2)/3)(arctan(sqrt(807)*3/179)/3), 120); # _Alois P. Heinz_, Nov 17 2020
%t A335864 With[{j = Sqrt[3] I, k = 3 Sqrt[3] Sqrt[269] I}, First@ RealDigits[Re[(1/3) (2 - (1/2) (1 + j) (179 + k)^(1/3) - (1/2) (1 - j) (179 - k)^(1/3))], 10, 97]] (* _Michael De Vlieger_, Nov 17 2020 *)
%Y A335864 Cf. A335862 (x1), A335863 (-x2).
%K A335864 nonn,cons,easy
%O A335864 0,1
%A A335864 _Wolfdieter Lang_, Jun 29 2020