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 A331448 #35 Jul 09 2025 04:50:52 %S A331448 0,8,92,596,1936,6020,11088,26260,42144,72296,107832,183340,222940, %T A331448 371100,466936,609916,804504,1139632,1288536,1813288,2012676,2536572, %U A331448 3142008,3997580,4230340,5430444,6331892,7360512,8262568,10367804 %N A331448 a(0) = 0 by convention; for n>0, a(n) is the number of edges in the n-th figure shown in A255011 (meaning the figure with 4n points on the perimeter). %C A331448 By Euler's formula, a(n) = A331449(n) + A255011(n) - 1. %H A331448 Zhao Hui Du, <a href="/A331448/b331448.txt">Table of n, a(n) for n = 0..136</a> (terms 0..52 from Lars Blomberg). %Y A331448 Cf. A255011, A331449. %Y A331448 For the circular analog see A006533, A007678, A007569, A135565. %K A331448 nonn %O A331448 0,2 %A A331448 _N. J. A. Sloane_, Jan 23 2020, based on a comment from _Michael De Vlieger_ in A255011 %E A331448 a(11)-a(29) from _Giovanni Resta_, Jan 28 2020