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 A267710 #10 Feb 07 2016 21:40:42 %S A267710 0,6,6,24,24,54,60,96,114,150,180,216,258,324,348,426,450,540,564,666, %T A267710 720,804,870,954,1056,1134,1230,1344,1416,1542,1614,1752,1842,1974, %U A267710 2100,2208,2346,2478,2628,2778,2898,3084,3180,3378,3474,3684,3822,4002,4176,4356 %N A267710 Number of unit triangular lattice cells enclosed by origin centered circle of diameter n. %C A267710 As n -> infinity, lim a(n)/(n^2) -> Pi/sqrt(3). %H A267710 Luca Petrone, <a href="/A267710/b267710.txt">Table of n, a(n) for n = 1..200</a> %Y A267710 Cf. A093602 (Pi/sqrt(3)). %K A267710 easy,nonn %O A267710 1,2 %A A267710 _Luca Petrone_, Jan 19 2016