A218226 Hilltop maps: number of n X n binary arrays indicating the locations of corresponding elements not exceeded by any horizontal, vertical or antidiagonal neighbor in a random 0..2 n X n array

1, 15, 497, 63309, 32362849, 66220959971, 542011629493301, 17745059393526510913, 2323828045898042282454885

Offset

1,2

Comments

Diagonal of A218233

Links

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

Example

Some solutions for n=3
..1..1..1....1..0..1....0..1..1....1..0..1....0..1..0....1..1..1....1..0..1
..0..0..1....0..0..1....1..0..0....0..0..0....0..0..0....1..1..1....0..0..1
..1..0..1....1..0..1....0..1..0....1..0..1....0..0..1....0..0..1....0..0..1

Crossrefs

Sequence in context: A285765 A287070 A062752 * A208099 A219057 A203525

Adjacent sequences: A218223 A218224 A218225 * A218227 A218228 A218229

Keyword

nonn

Author

R. H. Hardin Oct 24 2012

Status

approved