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 A300131 #21 Jan 12 2020 14:04:09
%S A300131 1,4,6,9,16,17,21,26,31,34,40,46
%N A300131 Largest number of points that can be placed on an n X n point grid so that no point is equally distant from two other points on the same straight line.
%C A300131 This definition is a 2-dimensional generalization of A003002 ("no 3-term arithmetic progressions"). It generalizes the definition of A296468 to include not only triples on horizontal or vertical lines but on any straight line.
%e A300131 On a 10 X 10 point grid 34 points (X) can be placed at most. Example:
%e A300131 . X . . . X X . . .
%e A300131 X X . . . X X . X .
%e A300131 X . X X . . . . X .
%e A300131 . . X . . . . X . X
%e A300131 . . . . . . . . X X
%e A300131 X X . . . . . . . .
%e A300131 X . X . . . . X . .
%e A300131 . X . . . . X X . X
%e A300131 . X . X X . . . X X
%e A300131 . . . X X . . . X .
%Y A300131 Cf. A003002, A296468.
%K A300131 nonn,hard,more
%O A300131 1,2
%A A300131 _Heinrich Ludwig_, Feb 26 2018
%E A300131 a(11) from _Bert Dobbelaere_, Jan 09 2020
%E A300131 a(12) from _Bert Dobbelaere_, Jan 12 2020