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 A122225 #13 Jun 10 2018 20:18:32
%S A122225 1,6,20,52,111,214,376,620,967,1452,2096,2952,4047,5422,7128,9236,
%T A122225 11773,14834,18450,22704,27675,33460,40090,47708,56383,66214,77276,
%U A122225 89748,103647,119206,136476,155592,176681,199858,225224,253104,283555,316692
%N A122225 (1/4)*number of nonsquare rectangles with corners on an n X n grid of points.
%H A122225 Jon E. Schoenfield, <a href="/A122225/b122225.txt">Table of n, a(n) for n = 3..500</a>
%H A122225 Jon E. Schoenfield, <a href="/A122225/a122225.txt">QBasic program</a>
%F A122225 a(n) = (A085582(n) - A002415(n))/4.
%e A122225 a(3)=1 because there are 4 rectangles that can be formed on the square grid [0,1,2] X [0,1,2]: {(0 0),(0 1),(2 0),(2 1)}, {(0 0),(0 2),(1 0),(1 2)}, {(0 1),(0 2),(2 1),(2 2)}, {(1 0),(1 2),(2 0),(2 2)}.
%Y A122225 Cf. A000537, A002415, A085582, A113751.
%K A122225 nonn
%O A122225 3,2
%A A122225 _Hugo Pfoertner_, Sep 29 2006
%E A122225 Corrected and extended by _Jon E. Schoenfield_, Oct 08 2006