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 A260666 #10 Nov 17 2015 21:11:22 %S A260666 0,0,1,2,1,3,6,13 %N A260666 Number of patterns with perimeter n in the planar net 3.3.4.3.4, mirrors and holes are excluded. %C A260666 Inspired by A057729 which is in planar net 3.3.3.3.3.3. %H A260666 Kival Ngaokrajang, <a href="/A260666/a260666.pdf">Illustration of initial terms</a> %Y A260666 Cf. A057729. %K A260666 nonn,more %O A260666 1,4 %A A260666 _Kival Ngaokrajang_, Nov 14 2015