A279452 - OEIS

A279452

Number of nonequivalent ways to place n points on an n X n square grid so that no more than 2 points are on a vertical or horizontal straight line.

1, 2, 14, 202, 4361, 126396, 4444935, 182567862, 8560638040, 451107721000

(list; graph; refs; listen; history; text; internal format)

OFFSET

1,2

COMMENTS

Rotations and reflections of placements are not counted. If they are to be counted, see A279444.

LINKS

EXAMPLE

There are a(3) = 14 nonequivalent ways to place 3 points on a 3 X 3 square grid under the condition mentioned above:

XX XX. XX. XX. XX. XX. X.X X.X X X X.. X.. X.. .X. .X.

..X ... X.. .X. ... ... .X. ... ... .XX .X. ..X XX. X.X

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

CROSSREFS

KEYWORD

nonn,more

AUTHOR

STATUS

approved