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 A337867 #29 May 31 2024 14:43:44 %S A337867 1,10,90,1414,23136,406093,7303813,134027098 %N A337867 Number of polyfetts (or polifetti) with n cells, identifying mirror images. %C A337867 A polyfett is a generalized polyabolo (or polytan). Its cells are equal isosceles right triangles on the quadrille grid, which may be joined along equal edges or at vertices. %C A337867 Polyfetts are to polyaboloes what polyplets (or polykings) are to polyominoes. %H A337867 Sean A. Irvine, <a href="https://github.com/archmageirvine/joeis/blob/master/src/irvine/oeis/a337/A337867.java">Java program</a> (github) %H A337867 George Sicherman, <a href="https://sicherman.net/polyfetts/">Catalogue of Polyfetts</a> %H A337867 George Sicherman, <a href="/A337867/a337867_1.c.txt">polyaboloes.c</a> %e A337867 For n = 2, a(2) = 10. Two polyabolo cells can be joined at edges to form 3 different diaboloes, or at corners to form 7 different proper difetts. %o A337867 (C) /* See link to Unix C program polyaboloes.c under LINKS. */ %Y A337867 Cf. A006074. %K A337867 nonn,hard,more %O A337867 1,2 %A A337867 _George Sicherman_, Sep 27 2020