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 A305200 #24 Feb 16 2025 08:33:54
%S A305200 5,7,6,4,1,2,7,2,3,0,3,1,4,3,5,2,8,3,1,4,8,2,8,9,2,3,9,8,8,7,0,6,8,4,
%T A305200 7,6,2,7,8,0,9,9,0,1,1,2,2,2,1,6,8,2,8,0,5,6,6,2,6,5,7,4,1,1,9,3,2,8,
%U A305200 5,3,4,4,4,1,4,2,4,7,1,9,9,4,5,2,0,5,2,8,7,1,0,4,3,9,0,4,4,8,7,5,8,9,5,9,8,8
%N A305200 Decimal expansion of the real part of continued exponential of i.
%D A305200 This is the real part of e^(i*e^(i*e^(i...))).
%H A305200 Eric Weisstein's World of Mathematics, <a href="https://mathworld.wolfram.com/LambertW-Function.html">Lambert W-Function</a>
%H A305200 Wikipedia, <a href="https://en.wikipedia.org/wiki/Lambert_W_function">Lambert W function</a>
%F A305200 Equals Re(i*LambertW(-i)). - _Alois P. Heinz_, May 27 2018
%F A305200 From _Vaclav Kotesovec_, Oct 02 2021: (Start)
%F A305200 Root of the equation exp(x*tan(x)) = cos(x)/x.
%F A305200 Equals Im(LambertW(i)). (End)
%e A305200 0.576412723031435283148289239887068476278...
%t A305200 RealDigits[Re[I*LambertW[-I]],10,120][[1]] (* _Harvey P. Dale_, Dec 01 2018 *)
%t A305200 RealDigits[x /. FindRoot[E^(x*Tan[x]) == Cos[x]/x, {x, 1/2}, WorkingPrecision -> 120]][[1]] (* _Vaclav Kotesovec_, Oct 02 2021 *)
%Y A305200 Cf. A049006, A077589, A077590, A191719, A305202.
%K A305200 nonn,cons
%O A305200 0,1
%A A305200 _Keerthi Vasan Gopala_, May 27 2018
%E A305200 More digits from _Alois P. Heinz_, May 27 2018