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 A131753 #2 Mar 30 2012 17:21:00
%S A131753 1,3,7,15,23,35,53,80,134,188,266,376
%N A131753 Number of ways of choosing the largest subset of {1,2,...,n} such that no two distinct elements differ by a perfect square > 1.
%Y A131753 Cf. A100719, A131752, A131754.
%K A131753 nonn
%O A131753 1,2
%A A131753 _Olivier Gérard_, Sep 17 2007