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 A208446 #53 May 16 2020 15:25:38 %S A208446 1,1,7,31,175,991,5881,35617,219871,1376095,8710537,55644337, %T A208446 358198369,2320792657,15120204295,98984058271,650725327231, %U A208446 4293779332927,28425752310361,188739799967425,1256510215733185 %N A208446 Duplicate of A172634. %H A208446 <a href="/A208446/b208446.txt">Table of n, a(n) for n = 0..20</a> %K A208446 dead %O A208446 0,3