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 A144996 #2 Mar 31 2012 10:22:10
%S A144996 5,55,27723,1084714750,2579620657453546201,
%T A144996 120904392155429552198250382953194665437,
%U A144996 29567118984689950525496948880094499522270777838300280083816338513462653571335
%N A144996 Denominators of an Egyptian fraction for 1/Sqrt[21] = 0.21821789...
%t A144996 a = {}; k = N[1/Sqrt[21], 1000]; Do[s = Ceiling[1/k]; AppendTo[a, s]; k = k - 1/s, {n, 1, 10}]; a (*Artur Jasinski*)
%Y A144996 A069139, A006487, A006526, A006525, A006524, A001466, A110820, A117116, A118323, A118324, A118325, A144835, A132480-A132574, A069261, A144984-A145003
%K A144996 frac,nonn
%O A144996 1,1
%A A144996 _Artur Jasinski_, Sep 28 2008