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 A102349 #8 Mar 30 2012 16:50:10 %S A102349 0,1,4,15,55,119 %N A102349 Numbers n such that binomial(n+1,2) is in A027568. %Y A102349 Cf. A027568. %K A102349 nonn,fini,full %O A102349 1,3 %A A102349 _N. J. A. Sloane_, Sep 06 2008