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 A248866 #22 Mar 13 2015 15:14:59 %S A248866 4,9,6,6,5,6,5,6,6,6,6 %N A248866 Discrete Heilbronn Triangle Problem: a(n) is twice the maximal area of the smallest triangle defined by three vertices that are a subset of n points on an n X n square lattice. %C A248866 For n points in an n X n square, find the three points that make the triangle with minimal area. a(n) is double the maximal area of this triangle. %C A248866 It is conjectured that the sequence has an infinite repetition of only two integers. %H A248866 Gordon Hamilton, <a href="http://youtu.be/rz5Ap8YnWoo">Unsolved K-12: Grade 8 Problems</a> %H A248866 Hiroaki Yamanouchi, <a href="/A248866/a248866.txt">examples for a(3)-a(13)</a> %e A248866 a(3) = 4 because 3 points can be chosen so the minimal triangle has area 2: %e A248866 .x. %e A248866 ... %e A248866 x.x %e A248866 a(6) = 6 because 3 points can be chosen so the minimal triangle has area 3: %e A248866 ..x..x %e A248866 ...... %e A248866 x..... %e A248866 .....x %e A248866 ...... %e A248866 x..x.. %e A248866 a(8) is greater than or equal to 4 because of this non-optimal arrangement: %e A248866 .....x.x %e A248866 ........ %e A248866 x.x..... %e A248866 ........ %e A248866 ........ %e A248866 x.x..... %e A248866 ........ %e A248866 .....x.x %e A248866 a(8) = 6 because 3 points can be chosen so the minimal triangle has area 3: %e A248866 ..x..x.. %e A248866 ........ %e A248866 x......x %e A248866 ........ %e A248866 ........ %e A248866 x......x %e A248866 ........ %e A248866 ..x..x.. %K A248866 nonn,more %O A248866 3,1 %A A248866 _Gordon Hamilton_, Mar 04 2015 %E A248866 a(5), a(7) and a(9) corrected and a(10)-a(13) added by _Hiroaki Yamanouchi_, Mar 09 2015