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 A101682 #2 Apr 30 2014 01:26:49 %S A101682 1,2,0,8,80,1152,21056,467840,12248064,369313280,12605643776, %T A101682 480491716608,20231074672640,932551401807872,46708494389084160, %U A101682 2525988902617776128,146694190329387352064,9105143756032486932480 %N A101682 Expansion of 2 - exp(-1 + sqrt(1-4x)). %Y A101682 Cf. A000806. %K A101682 nonn %O A101682 0,2 %A A101682 _Ralf Stephan_, Dec 13 2004