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 A296994 #34 May 02 2019 08:15:31
%S A296994 1,3,4,7,10,14,18,20,23,27,31,36,42,48,54,61,68,76,84,92,98
%N A296994 Largest number of points that can be selected from an n X n X n triangular point grid so that no selected point is equally distant from two other selected points on a straight line, which is parallel to one side of the grid.
%C A296994 This sequence generalizes the idea of A003002 ("no 3-term arithmetic progressions") for triangular point grids.
%C A296994 For the same idea applied to square grids see A296468 and A300131.
%e A296994 At most 54 points (X) can be chosen from a 15 X 15 X 15 triangular point grid under the condition mentioned above. Example:
%e A296994 o
%e A296994 X X
%e A296994 X o X
%e A296994 o X X o
%e A296994 X X o X X
%e A296994 X o o o o X
%e A296994 o o X o X o o
%e A296994 o o o o o o o o
%e A296994 o o X X o X X o o
%e A296994 o X o o X X o o X o
%e A296994 X X o o X o X o o X X
%e A296994 X o X X o o o o X X o X
%e A296994 o X X o o X o X o o X X o
%e A296994 X X o X X o o o o X X o X X
%e A296994 X o o o o X X o X X o o o o X
%Y A296994 Cf. A296468, A300131.
%K A296994 nonn,nice,hard,more
%O A296994 1,2
%A A296994 _Heinrich Ludwig_, Mar 26 2018
%E A296994 a(20) from _Heinrich Ludwig_, Apr 24 2018
%E A296994 a(21) from _Heinrich Ludwig_, May 01 2018