A279454 - OEIS

A279454

Number of nonequivalent ways to place k>=0 points on an n X n square grid so that no more than 2 points are on a vertical or horizontal straight line.

2, 6, 54, 1026, 38931, 2198241, 167110761, 16248457762, 1960813221768

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

OFFSET

1,1

COMMENTS

Row sum of triangle A279453.

Rotations and reflections of a placement are not counted. For numbers if they are to be counted, see A197458.

LINKS

Table of n, a(n) for n=1..9.

CROSSREFS

Cf. A197458, A279453.

Sequence in context: A219692 A085078 A152543 * A306021 A122593 A267348

Adjacent sequences: A279451 A279452 A279453 * A279455 A279456 A279457

KEYWORD

nonn,more

AUTHOR

Heinrich Ludwig, Dec 24 2016

STATUS

approved