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

3,2

Comments

Column 6 of A235453.

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

Links

Table of n, a(n) for n=3..14.

Example

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).

Sequence in context: A200453 A283638 A375331 * A200557 A077494 A217142

Adjacent sequences: A235454 A235455 A235456 * A235458 A235459 A235460

Keyword

nonn,more

Author

Heinrich Ludwig, Jan 12 2014

Extensions

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

Status

approved