A235458 Number of non-equivalent (mod D_4) ways to arrange 7 points on an n X n square grid so that no three points are collinear.

28, 3385, 134353, 1958674, 19929645, 138586349, 753795278, 3356614240, 13108210508, 44374441652, 137349454120

Offset: 4

Author

Heinrich Ludwig, Jan 12 2014

Keywords

• nonn
• more

Comments

Column 7 of A235453.

Without the restriction "non-equivalent (mod D_4)" the numbers are given by A194192, n >= 4.

Examples

			There are a(4) = 28 non-equivalent ways to place 7 points (X) on a 4 X 4 grid. Example:
   . X X .
   . . . X
   X . . X
   X X . .
		

Crossrefs

Cf. A235453, A194192, A235454 (3 points), A235455 (4 points), A235456 (5 points), A235457 (6 points).

Extensions

a(13), a(14) from Heinrich Ludwig, Nov 16 2016