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 A050631 #9 Oct 15 2019 00:03:02 %S A050631 2,7,43,136,10158,85927342,738024797793593 %N A050631 a(1)=2; for n>1, a(n)^2 is next smallest nontrivial square containing a(n-1)^2 as a substring. %C A050631 Starting with a(2)=7, the sequence is identical to A050633. %Y A050631 Cf. A050630, A048560, A050637. %K A050631 nonn,base,more %O A050631 1,1 %A A050631 _Patrick De Geest_, Jul 15 1999 %E A050631 a(7) from _Max Alekseyev_, Feb 15 2012