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 A333459 #13 Jun 03 2020 05:27:15 %S A333459 5,69,785,4177,12681,33601,71777,125389,238801,379793,548293,878397, %T A333459 1203101,1673693,2311477,3063609,3934365,4931077,6501545,7873689, %U A333459 9852941,12071685,14067849,17728005,20417893,24047817,29003717 %N A333459 Number of vertices in an diagonal-edged (or diamond-shaped) checkerboard with width and height 2*n-1 (see Comments in A333434 for definition). %C A333459 See A333434 for the definition and images of the checkerboard. %Y A333459 Cf. A333434 (regions), A333458 (n-gons), A333460 (edges), A333035, A333031, A330850. %K A333459 nonn,more %O A333459 1,1 %A A333459 _Scott R. Shannon_ and _N. J. A. Sloane_, Mar 22 2020 %E A333459 a(8)-a(27) from _Lars Blomberg_, Jun 03 2020