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A235456 Number of non-equivalent (mod D_4) ways to arrange 5 points on an n X n square grid so that no three points are collinear. 6
5, 217, 3192, 27041, 149217, 650566, 2317137, 7124316, 19459757, 48617666, 111797647, 241575473 (list; graph; refs; listen; history; text; internal format)
OFFSET

3,1

COMMENTS

Column 5 of A235453.

Without the restriction "non-equivalent (mod D_4)" the numbers are given by A194190, n >= 3.

LINKS

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

EXAMPLE

There are a(3) = 5 non-equivalent ways to place 5 points (X) on a 3 X 3 grid:

  X . X    X . X    . X X    X X .    X . X

  X . X    X . .    X . X    X . .    X X .

  . X .    . X X    . X .    . X X    . X .

CROSSREFS

Cf. A235453, A194190, A235454 (3 points), A235455 (4 points), A235457 (6 points), A235458 (7 points)

Sequence in context: A206457 A291806 A119657 * A159808 A159317 A345465

Adjacent sequences:  A235453 A235454 A235455 * A235457 A235458 A235459

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 October 22 22:35 EDT 2021. Contains 348180 sequences. (Running on oeis4.)