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 A300701 #24 Apr 03 2018 10:17:07 %S A300701 1,3,13,87,805,9303,128533 %N A300701 a(n) = number of faces in a concertina n-cube. %H A300701 Tilman Piesk, <a href="https://en.wikiversity.org/wiki/Formulas_in_predicate_logic">Formulas in predicate logic</a> (Wikiversity) %H A300701 Tilman Piesk, <a href="https://commons.wikimedia.org/wiki/File:Concertina_cube_Hasse_diagram.png">Skeleton</a> and <a href="https://commons.wikimedia.org/wiki/File:Concertina_cube_with_direction_colors;_ortho_rhomb.png">solid</a> representation of a concertina cube. %e A300701 A concertina 3-cube has 26 0-faces (vertices), 42 1-faces (edges), 18 2-faces and 1 3-face (the polyhedron itself). Together this makes a(3) = 87 faces. %Y A300701 Row sums of A300700. %K A300701 nonn,more %O A300701 0,2 %A A300701 _Tilman Piesk_, Mar 11 2018