A198446 Number of 2nX2n 0..2 arrays with values 0..2 introduced in row major order and each element unequal to exactly two horizontal and vertical neighbors

3, 177, 26704, 13048509, 22496409154

Offset

1,1

Comments

Diagonal of A198452

Links

Table of n, a(n) for n=1..5.

Example

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

Crossrefs

Sequence in context: A268949 A113270 A091324 * A216967 A217443 A270245

Adjacent sequences: A198443 A198444 A198445 * A198447 A198448 A198449

Keyword

nonn

Author

R. H. Hardin Oct 25 2011

Status

approved