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 A307519 #12 Apr 22 2019 11:46:32 %S A307519 2,1,2,6,10,17,34,72,142,288,585,1195,2413,4898 %N A307519 a(n) is the number of canonical polygons with 4n edges having exactly 4 lines of reflection symmetry. %H A307519 Lars Blomberg, <a href="/A307519/a307519.pdf">Examples of canonical polygons with exactly 4 lines of reflection symmetry</a> %Y A307519 Cf. A052436, A307387, A307391, A307426, A307454, A307455, A307456, A307519. %K A307519 nonn,more %O A307519 1,1 %A A307519 _Lars Blomberg_, Apr 12 2019