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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

%I #10 Nov 16 2016 15:51:45

%S 1,142,4699,77970,672506,4338248,21167201,85351595,294664274,

%T 911848844,2528561187,6501165477

%N 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.

%C Column 6 of A235453.

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

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

%e . X X

%e X . X

%e X X .

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

%K nonn,more

%O 3,2

%A _Heinrich Ludwig_, Jan 12 2014

%E a(13), a(14) from _Heinrich Ludwig_, Nov 16 2016

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Last modified April 24 18:05 EDT 2024. Contains 371962 sequences. (Running on oeis4.)