

A235458


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


6



28, 3385, 134353, 1958674, 19929645, 138586349, 753795278, 3356614240, 13108210508, 44374441652, 137349454120
(list;
graph;
refs;
listen;
history;
text;
internal format)



OFFSET

4,1


COMMENTS

Column 7 of A235453.
Without the restriction "nonequivalent (mod D_4)" the numbers are given by A194192, n >= 4.


LINKS

Table of n, a(n) for n=4..14.


EXAMPLE

There are a(4) = 28 nonequivalent 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).
Sequence in context: A285151 A232520 A061787 * A128506 A164655 A291585
Adjacent sequences: A235455 A235456 A235457 * A235459 A235460 A235461


KEYWORD

nonn,more


AUTHOR

Heinrich Ludwig, Jan 12 2014


EXTENSIONS

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


STATUS

approved



