A207222 Number of n X n 0..2 arrays avoiding the patterns z z+1 z or z z-1 z in any row, column or nw-se diagonal.

3, 81, 6819, 3447649, 8779228417, 105855104360481, 6152504033864688529, 1755834487701036618450529

Offset

1,1

Comments

Diagonal of A207228

Links

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

Example

Some solutions for n=4
..2..0..1..2....0..1..2..2....2..0..0..1....0..2..0..0....2..1..0..2
..0..2..2..0....2..2..0..0....1..1..0..2....0..1..2..0....1..2..2..1
..2..2..0..1....0..2..2..0....0..2..1..0....1..0..2..0....1..0..2..0
..2..1..0..2....0..1..1..1....2..2..2..0....1..2..2..2....0..0..2..0

Crossrefs

Sequence in context: A223717 A395174 A223825 * A207007 A223783 A223969

Adjacent sequences: A207219 A207220 A207221 * A207223 A207224 A207225

Keyword

nonn

Author

R. H. Hardin, Feb 16 2012

Status

approved