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 A127815 #11 Jan 28 2022 16:23:54
%S A127815 1,2,6,30,330,257070,128005692870,23279147893155496537470,
%T A127815 388475314992168993748220639081347493631827670,
%U A127815 102339769648127358726761918460732576814168548432921287355299929744910591862606847215978930
%N A127815 a(n) = denominator of b(n), where b(1) = 2, b(n) = b(n-1) - 1/b(n-1).
%F A127815 For n >= 2, a(n) = a(n-1)*A127814(n-1).
%e A127815 A127814/A127815 = 2, 3/2, 5/6, -11/30, 779/330, 497941/257070, 181860254581/128005692870, ...
%t A127815 f[l_List] := Append[l, l[[ -1]] - 1/l[[ -1]]];Denominator[Nest[f, {2}, 10]] (* _Ray Chandler_, Feb 07 2007 *)
%Y A127815 Cf. A127814.
%K A127815 easy,frac,nonn
%O A127815 1,2
%A A127815 _Leroy Quet_, Jan 30 2007
%E A127815 Extended by _Ray Chandler_, Feb 07 2007