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 A139752 #2 Mar 31 2012 14:39:55 %S A139752 2,3,5,7,2,5,17,37,2,3,11,83,3,7,19,67,5,13,29,53,5,41 %N A139752 Primes arising in A139750. %K A139752 base,easy,nonn,less %O A139752 1,1 %A A139752 _Ctibor O. Zizka_, May 19 2008