A235457 Number of non-equivalent (mod D_4) ways to arrange 6 points on an n X n square grid so that no three points are collinear.

1, 142, 4699, 77970, 672506, 4338248, 21167201, 85351595, 294664274, 911848844, 2528561187, 6501165477

Offset: 3

Author

Heinrich Ludwig, Jan 12 2014

Keywords

• nonn
• more

Comments

Column 6 of A235453.

Without the restriction "non-equivalent (mod D_4)" the numbers are given by A194191, n >= 3.

Examples

			There is a(3) = 1 way to place 6 points (X) on a 3 X 3 grid (without rotations and reflections):
   . X X
   X . X
   X X .
		

Crossrefs

Cf. A235453, A194191, A235454 (3 points), A235455 (4 points), A235456 (5 points), A235458 (7 points).

Extensions

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