A218632 Hilltop maps: number of n X n binary arrays indicating the locations of corresponding elements not exceeded by any horizontal, diagonal or antidiagonal neighbor in a random 0..3 n X n array

1, 15, 511, 65523, 33546641, 68702054721, 562806164441653, 18442026828339805665

Offset

1,2

Comments

Diagonal of A218638

Links

Table of n, a(n) for n=1..8.

Example

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

Crossrefs

Sequence in context: A092561 A218312 A218280 * A218235 A212739 A009068

Adjacent sequences: A218629 A218630 A218631 * A218633 A218634 A218635

Keyword

nonn

Author

R. H. Hardin Nov 03 2012

Status

approved