A279444 Number of 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, 6, 78, 1428, 34020, 1005720, 35526120, 1460297160, 68483325960, 3608847088560, 211125189789360, 13577790144108960, 952129825291925280, 72303731169467878080, 5911241852357814772800, 517670861532464104264800, 48347072773751574327304800

Offset: 1

Author

Heinrich Ludwig, Dec 23 2016

Keywords

• nonn

Comments

Rotations and reflections of placements are counted. If they are to be ignored, see A279452.

Links

• Hiroaki Yamanouchi, Table of n, a(n) for n = 1..100

Crossrefs

Cf. A279452, A279445.

Extensions

a(11)-a(17) from Hiroaki Yamanouchi, Jan 04 2017