A198007 Number of n X n 0..4 arrays with each element x equal to the number of its horizontal and vertical neighbors equal to 3,3,0,1,2 for x=0,1,2,3,4.

1, 7, 51, 1165, 80519, 12594359, 5423217685, 5925057763939, 16185578398527540

Offset

1,2

Comments

Every 0 is next to 0 3's, every 1 is next to 1 3's, every 2 is next to 2 0's, every 3 is next to 3 1's, every 4 is next to 4 2's.

Diagonal of A198013.

Links

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

Example

Some solutions for n=4:
..2..0..0..0....0..1..3..1....0..0..1..0....2..0..0..2....0..0..0..0
..0..0..0..2....2..0..1..0....0..1..3..2....0..1..0..0....0..0..0..0
..0..0..0..2....2..0..2..0....0..0..1..0....2..3..1..2....0..0..1..0
..2..0..0..0....0..0..2..0....0..0..0..2....0..1..0..0....0..1..3..1

Crossrefs

Sequence in context: A198087 A124271 A220224 * A156751 A352242 A138849

Adjacent sequences: A198004 A198005 A198006 * A198008 A198009 A198010

Keyword

nonn

Author

R. H. Hardin, Oct 20 2011

Status

approved