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 A337571 #40 Oct 27 2023 12:07:56
%S A337571 1,5,3,3,7,5,1,1,6,8,7,5,5,2,0,4,2,8,8,1,1,8,0,4,1,4,1,3,2,8,2,2,2,6,
%T A337571 8,3,6,7,0,9,7,2,3,6,3,4,5,5,0,4,8,2,0,8,1,5,4,2,0,3,7,6,0,3,9,6,8,3,
%U A337571 9,9,1,9,9,8,9,1,5,6,1,6,2,4,6,9,3,9,8,8,1,7,6,2,3,3,5,5,9
%N A337571 Decimal expansion of the real positive solution to x^4 = x+4.
%C A337571 x = (4 + (4 + (4 + ... )^(1/4))^(1/4))^(1/4).
%C A337571 The negative value (-1.5337511687...) is the real negative solution to x^4 = 4-x.
%H A337571 <a href="/index/Al#algebraic_04">Index entries for algebraic numbers, degree 4</a>
%F A337571 Equals sqrt(sqrt(1/s) - s/16) + sqrt(s/16) where s = (sqrt(16804864/27) + 32)^(1/3) - (sqrt(16804864/27) - 32)^(1/3). [Simplified by _Michal Paulovic_, Jun 22 2021]
%e A337571 1.5337511687552...
%t A337571 RealDigits[x /. FindRoot[x^4 - x - 4, {x, 1}, WorkingPrecision -> 100], 10, 90][[1]] (* _Amiram Eldar_, Sep 03 2020 *)
%o A337571 (PARI) solve(n=0,2,n^4-n-4)
%o A337571 (PARI) polroots(n^4-n-4)[2]
%o A337571 (PARI) polrootsreal(n^4-n-4)[2] \\ _Charles R Greathouse IV_, Oct 27 2023
%o A337571 (MATLAB) format long; solve('x^4-x-4=0'); ans(1), (eval(ans))
%Y A337571 Cf. A337570, A060007, A294644.
%K A337571 nonn,cons
%O A337571 1,2
%A A337571 _Michal Paulovic_, Sep 01 2020