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 A375935 #26 Oct 16 2024 21:48:30
%S A375935 1,3,119,72697201,466125047039779152001,
%T A375935 1298332088620573402611989909424448036756809624806401
%N A375935 Denominator of rational number tan(2^(n-1)*arctan(1/A024810(n))).
%C A375935 r(n) = tan(2^(n-1)*arctan(1/A024810(n))) is always a rational number such that its limit lim_{n->oo} r(n)=1.
%H A375935 Sanjar M. Abrarov, Rajinder K. Jagpal, Rehan Siddiqui, and Brendan M. Quine, <a href="https://doi.org/10.3390/mca29020017">An Iterative Method for Computing π by Argument Reduction of the Tangent Function</a>, Math. Comput. Appl. 2024, 29(2), 17.
%F A375935 a(n) = denominator(tan(2^(n-1)*arctan(1/A024810(n)))).
%t A375935 a[n_] := Module[{}, z[n] = (Floor[2^(n + 1)/\[Pi]] + I)^2^(n - 1); Denominator[Im[z[n]]/Re[z[n]]]];
%t A375935 Print[a[1], " ", a[2], " ", a[3], " ", a[4], " ", a[5], " ", a[6]];
%Y A375935 Cf. A024810, A374723 (numerators).
%K A375935 nonn,frac
%O A375935 1,2
%A A375935 _Sanjar Abrarov_, Sep 03 2024