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 A141225 #5 Mar 30 2012 17:22:50
%S A141225 1,4,1,4,8,16,8,12,16,36,9,60,16,16,8,12,12,12,12,36,16,16,25,4,16,8,
%T A141225 5,12,24,64,12,8,4,4,25,16,4,8,1,20,16,4,20,12,4,4,9,8,4,4,4,4,12,4,4,
%U A141225 4,4,12,9,4,8,4,8,12,8,4,4,8,4,16,12,20,4,8,4,4,16,4,4,4,4,4,4,4,4,4,8,4,4
%N A141225 Number of points having maximal visibility in a square n x n lattice.
%C A141225 Sequence A141224 gives the maximum number of points visible from some point. By symmetry, when a(n) is odd, the central point in the lattice can see the maximal number of points. When a(n)=1, the central point is the only such point. See A141226 for the n x n lattices that have such a central point.
%H A141225 T. D. Noe, <a href="/A141225/b141225.txt">Table of n, a(n) for n=1..1000</a>
%t A141225 Table[mx=0; pts=0; Do[cnt=0; Do[If[GCD[c-a,d-b]<2, cnt++ ], {a,n}, {b,n}]; If[cnt>mx, mx=cnt; pts=1, If[cnt==mx, pts++ ]], {c,n}, {d,n}]; pts, {n,20}]
%K A141225 nonn
%O A141225 1,2
%A A141225 _T. D. Noe_, Jun 15 2008