A184367 1/3 the number of (n+1)X(n+1) 0..2 arrays with every 2X2 subblock having at least two equal elements connected horizontally or vertically.

21, 2755, 2167173, 10378244309, 301753233626727, 53293289955084658949, 57168347029530545962203193, 372482322079037724494019844619359

Offset: 1

Author

R. H. Hardin Jan 12 2011

Keywords

• nonn

Comments

Diagonal of A184376

Examples

			Some solutions for 3X3 with a(1,1)=0
..0..1..2....0..2..1....0..0..2....0..0..2....0..0..1....0..2..1....0..1..0
..2..1..1....1..1..1....2..2..2....0..0..2....2..0..2....0..0..1....0..1..2
..1..1..2....0..1..1....0..1..0....1..1..2....2..0..0....0..2..1....2..1..1