A197055 Number of n X n 0..4 arrays with each element equal to the number of its horizontal and vertical neighbors equal to 2

1, 2, 6, 18, 48, 211, 1685, 17107, 194842, 2735810, 54757712, 1541398741, 56647655849, 2661035439470

Offset

1,2

Comments

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

Diagonal of A197061

Links

Table of n, a(n) for n=1..14.

Example

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

Crossrefs

Sequence in context: A059413 A377118 A256828 * A258625 A062026 A048495

Adjacent sequences: A197052 A197053 A197054 * A197056 A197057 A197058

Keyword

nonn

Author

R. H. Hardin Oct 09 2011

Status

approved