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 A344657 #27 Jul 21 2021 09:09:30 %S A344657 3,10,85,310,999,2299,4674,8878,14539,23116,35922,53830,74685,106957, %T A344657 140887,183718,240108,315997,392049,497518,599596,730762,888903, %U A344657 1083277,1257270,1502830,1760371,2047792,2362620,2771437,3129933,3629443,4107994,4670305,5245447,5921755 %N A344657 Number of vertices formed by infinite lines when connecting all vertices and all points that divide the sides of an equilateral triangle into n equal parts. %C A344657 See A344279 for other images of the polygons. %H A344657 Scott R. Shannon, <a href="/A344657/a344657.png">Image of the vertices for n = 3</a>. %H A344657 Scott R. Shannon, <a href="/A344657/a344657_1.png">Image of the vertices for n = 4</a>. %F A344657 a(n) = A344896(n) - A344279(n) + 1. %Y A344657 Cf. A344279 (number of polygons), A344896 (number of edges), A092867 (number polygons inside the triangle), A346446 (number of k-gons), A345649, A146212. %K A344657 nonn %O A344657 1,1 %A A344657 _Scott R. Shannon_, Jun 24 2021