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 A075398 #19 Jul 03 2012 10:24:35 %S A075398 4,8,32,128,8192,131072,524288,2147483648,2305843009213693952, %T A075398 618970019642690137449562112,162259276829213363391578010288128, %U A075398 170141183460469231731687303715884105728 %N A075398 Duplicate of A072868. %K A075398 dead %O A075398 1,1 %A A075398 _Zak Seidov_, Oct 11 2002