A187526 Number of (n+1)X(n+1) 0..2 arrays with each 2X2 subblock determinant nonzero and the array of 2X2 subblock determinants symmetric under 90 degree rotation.

50, 8, 3790, 1476, 3607148, 296232

Offset: 1

Author

R. H. Hardin Mar 10 2011

Keywords

• nonn

Comments

Column 2 of A187528

Examples

			Some solutions for 4X4
..2..1..0..1....2..0..2..0....1..0..1..0....2..2..0..2....2..2..2..2
..1..0..1..2....0..1..0..1....0..1..0..1....2..1..1..2....1..0..1..0
..1..1..0..1....2..2..2..2....1..2..1..2....2..2..0..2....2..2..0..2
..1..0..1..0....1..2..1..2....0..1..0..1....2..1..1..2....2..1..1..0