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 A069685 #13 Feb 16 2021 17:54:22
%S A069685 1,12,180,1680,12600,166320,2522520,576576,22054032,465585120,
%T A069685 2560718160,64250746560,348024877200,1124388064800,4990906206000,
%U A069685 165032631878400,350694342741600,2599263952084800,101515697684200800
%N A069685 Denominators of coefficients in -log(1+x)log(1-x) power series.
%F A069685 a(n) = n*A076100(n) (conjectured). - _F. Chapoton_, Nov 09 2009
%o A069685 (PARI) my(x='x+O('x^50), v=Vec(-log(1+x)*log(1-x))); apply(denominator, vector(#v\2, k, v[2*k-1])) \\ _Michel Marcus_, Feb 16 2021
%Y A069685 Cf. A049281, A076100.
%K A069685 easy,frac,nonn
%O A069685 1,2
%A A069685 _Benoit Cloitre_, May 03 2002