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 A050639 #6 Mar 05 2015 12:20:13 %S A050639 3,7,43,1293,154957,20214998707,118659019449999845043, %T A050639 5566692951015284052000000000020214998707, %U A050639 21637689578064053873124753714430240419600000000000000000000118659019449999845043 %N A050639 a(1) = 3; a(n+1)^2 is next smallest square ending with a(n)^2. %Y A050639 Cf. A050638, A048562, A050631. %K A050639 nonn,base %O A050639 1,1 %A A050639 _Patrick De Geest_, Jul 15 1999 %E A050639 More terms from Ulrich Schimke (ulrschimke(AT)aol.com), Nov 06 2001