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 A330851 #27 May 31 2020 05:49:52 %S A330851 108,172,294,522,848,1352,2046,3032,4260,5958,8048,10806,14082,18070, %T A330851 22778,28646,35314,43436,52676,63370,75290,89330,104908,122816,142476, %U A330851 164644,188954,216686,246584,280386,317186,357658,401138,448884,500014,556706,617160 %N A330851 The number of edges inside a cross with width 3 and height n (see Comments in A331455 for definition) formed by the straight line segments mutually connecting all vertices and all points. %C A330851 See the links in A331455 for images of the crosses. %H A330851 Lars Blomberg, <a href="/A330851/b330851.txt">Table of n, a(n) for n = 2..50</a> %Y A330851 Cf. A331455 (regions), A330848 (n-gons), A330850 (vertices), A333035 (cross with equal length arms). %K A330851 nonn %O A330851 2,1 %A A330851 _Scott R. Shannon_ and _N. J. A. Sloane_, Mar 07 2020 %E A330851 Corrected offset and a(11) and beyond from _Lars Blomberg_, May 31 2020