A296468 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 row or column.

1, 4, 6, 11, 17, 24, 28, 32, 40, 47, 57, 66, 78, 90

Offset: 1

Author

Heinrich Ludwig, Dec 13 2017

Keywords

• nonn
• hard
• more
• nice

Comments

This sequence is a 2-dimensional generalization of A003002 ("no 3-term arithmetic progressions").

Examples

			Up to 66 points (x) may be placed on a 12 X 12 point grid. Example with two symmetry axes:
x x . x x . . . . x x .
x . x . . x x . . x . x
. x x . . . . x x . x x
x . . . . x x . x x . .
x . . . x . x x . x . .
. x . x . . . x x . x .
. x . x x . . . x . x .
. . x . x x . x . . . x
. . x x . x x . . . . x
x x . x x . . . . x x .
x . x . . x x . . x . x
. x x . . . . x x . x x
		

Crossrefs

Cf. A003002, A193838, A300131.

Extensions

a(13)-a(14) from Bert Dobbelaere, Jan 06 2020