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 A125578 #7 Jun 21 2023 12:34:19
%S A125578 8,2,4,1,3,2,3,1,2,3,0,2,5,2,2,4,2,2,9,6,0,9,5,6,7,8,5,7,7,1,9,9,1,1,
%T A125578 0,8,1,4,2,6,8,9,8,6,6,7,4,8,2,8,9,9,9,1,7,3,2,6,1,6,6,8,7,3,9,0,6,6,
%U A125578 6,2,7,0,9,6,9,4,1,3,2,7,0,1,5,6,6,1,3,0,0,3,5,5,0,2,1,1,3,5,5,7,2,9
%N A125578 Decimal expansion of positive root of x^2 = cos(x).
%C A125578 Both roots have same magnitude: x = +-0.824132312302...
%C A125578 Fixed point of cos(x)/x function. - _Michal Paulovic_, Jun 13 2023
%e A125578 0.824132312302522422960956785771991108142689866748289991732...
%p A125578 Digits:=100;fsolve(cos(x)/x-x,x); # _Michal Paulovic_, Jun 13 2023
%t A125578 RealDigits[FindRoot[Cos[x] == x^2, {x, {.7, 1}}, WorkingPrecision -> 120][[1, 2, 1]], 10, 111][[1]]
%o A125578 (PARI) solve(x=0,1,cos(x)-x^2) \\ _Charles R Greathouse IV_, Apr 14 2014
%Y A125578 Cf. A003957, A124597.
%K A125578 cons,nonn
%O A125578 0,1
%A A125578 Denton J. Dailey (djd1497(AT)aol.com), Jan 03 2007