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 A028492 #14 May 25 2019 01:40:42 %S A028492 0,1,6,20,55,119,229,402,667,1019,1536,2216,3049,4168,5546,7203,9278, %T A028492 11755,14597,18054,22138,26625,31958,38120,44821,52764,61663,71204, %U A028492 82250,94479,107680,122740,139224,156699,176450,198176,220883 %N A028492 Similarity classes of triangles which can be drawn using the lattice points in an n X n grid for vertices. %H A028492 Sean A. Irvine, <a href="https://github.com/archmageirvine/joeis/blob/master/src/irvine/oeis/a028/A028492.java">Java program</a> (github) %H A028492 D. Rusin, <a href="http://www.math.niu.edu/~rusin/known-math/97/triangles.grid">Lattice Problem (Triangles)</a> [Broken link] %H A028492 D. Rusin, <a href="/A028419/a028419.grid.txt">Lattice Problem (Triangles)</a> [Cached copy] %Y A028492 Cf. A028419. %K A028492 nonn %O A028492 0,3 %A A028492 _David J. Rusin_ %E A028492 Extended by _Ray Chandler_, May 03 2011