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

1,2

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.

Sequence in context: A268555 A131926 A132866 * A094419 A229044 A300874

Adjacent sequences: A279441 A279442 A279443 * A279445 A279446 A279447

Keyword

nonn

Author

Heinrich Ludwig, Dec 23 2016

Extensions

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

Status

approved