A198278 Number of 2nX2n 0..2 arrays with values 0..2 introduced in row major order and each element equal to exactly two horizontal and vertical neighbors

1, 4, 100, 8784, 2823604, 3337609528

Offset

1,2

Comments

Diagonal of A198285

Links

Table of n, a(n) for n=1..6.

Example

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

Crossrefs

Sequence in context: A224385 A249939 A224018 * A202990 A324096 A202989

Adjacent sequences: A198275 A198276 A198277 * A198279 A198280 A198281

Keyword

nonn

Author

R. H. Hardin Oct 23 2011

Status

approved