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 A339770 #12 Apr 26 2023 07:03:07 %S A339770 1,15,170,2766,46127,811265,14605298,268039329 %N A339770 Number of polyfetts (or polifetti) with n cells, distinguishing mirror images. %C A339770 A polyfett [polifetto] is a generalized polyabolo [polytan]. It is formed by joining isosceles right triangles on the quadrille grid along edges and at corners. %H A339770 George Sicherman, <a href="https://sicherman.net/polyfetts/">Catalogue of Polyfetts</a> %e A339770 For n=2 there are 4 diaboloes and 11 proper difetts, distinguishing mirror images. See the link. %Y A339770 Cf. A337867 (number of polyfetts with n cells, identifying mirror images). %K A339770 nonn,hard,more %O A339770 1,2 %A A339770 _George Sicherman_, Dec 16 2020