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 A309211 #26 Jun 27 2025 19:37:05
%S A309211 2,9,8,4,7,0,4,5,8,5,3,5,7,8,8,6,8,1,5,5,5,9,7,9,1,2,3,4,6,1,5,6,4,3,
%T A309211 1,6,4,4,8,5,3,9,7,0,6,9,1,2,3,8,4,4,2,6,0,4,9,7,0,6,1,5,6,9,4,0,9,9,
%U A309211 8,0,5,7,3,3,3,9,9,6,7,9,4,2,0,6,8,3,3,9,7,9,3,3,8,3,1,7,9,4,4,5,6,4,2,8,5,8
%N A309211 Decimal expansion of a solution to x = 3*tanh(x).
%e A309211 2.9847045853578868155597912346...
%p A309211 Digits := 120 ; fsolve(x=3*tanh(x),x,0..10.) ; # _R. J. Mathar_, Jul 30 2019
%t A309211 RealDigits[x/.FindRoot[x==3Tanh[x],{x,3},WorkingPrecision->120]][[1]] (* _Harvey P. Dale_, Jul 30 2019 *)
%o A309211 (PARI) A309211_first(n)={localprec(n\.9+9);digits(solve(x=2.9,3,tanh(x)*3-x)\10^(1-n))} \\ _M. F. Hasler_, Jan 27 2023
%Y A309211 Cf. A309207 (continued fraction expansion), A309208.
%K A309211 nonn,cons
%O A309211 1,1
%A A309211 _N. J. A. Sloane_, Jul 30 2019
%E A309211 More terms from _Daniel Suteu_, Jul 30 2019