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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. 6
1, 142, 4699, 77970, 672506, 4338248, 21167201, 85351595, 294664274, 911848844, 2528561187, 6501165477 (list; graph; refs; listen; history; text; internal format)
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
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: A219146 A200453 A283638 * A200557 A077494 A217142
KEYWORD
nonn,more
AUTHOR
Heinrich Ludwig, Jan 12 2014
EXTENSIONS
a(13), a(14) from Heinrich Ludwig, Nov 16 2016
STATUS
approved

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Last modified May 19 19:42 EDT 2024. Contains 372702 sequences. (Running on oeis4.)