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 A334459 #17 Jun 02 2025 22:33:02 %S A334459 0,5,24,86,265,582,1260,2235,3861,6055,9416,13366,19409,26296,35408, %T A334459 46569,60945,76527,97432,119703,147753,178670,216844,256401,306825, %U A334459 358719,421848,487960,567617,647259,747596,847765,966609,1088541,1232280,1376016,1548265 %N A334459 Number of edges in a polygon whose boundary consists of n+2 equally spaced points around a semicircle and n+2 equally spaced points along the diameter (a total of 2n+2 points). See Comments for precise definition. %C A334459 A semicircular polygon with 2n+2 points is created by placing n+2 equally spaced vertices along the semicircle's arc (including the two end vertices). Also place n+2 equally spaced vertices along the diameter (again including the same two end vertices). Now connect every pair of vertices by a straight line segment. The sequence gives the number of edges in the resulting figure. %H A334459 Lars Blomberg, <a href="/A334459/b334459.txt">Table of n, a(n) for n = 0..50</a> %Y A334459 Cf. A333519, A334458 %K A334459 nonn %O A334459 0,2 %A A334459 _Lars Blomberg_, May 01 2020