A187698 Number of (n+1)X(n+1) 0..3 arrays with each 2X2 subblock determinant nonzero and the array of 2X2 subblock determinants symmetric under horizontal and vertical reflection.

192, 74, 87258, 22738, 1089964504

Offset: 1

Author

R. H. Hardin Mar 12 2011

Keywords

• nonn

Comments

Column 3 of A187699

Examples

			Some solutions for 4X4
..2..2..1..2....0..3..0..3....1..2..2..2....2..3..1..0....0..1..0..1
..3..0..3..0....2..1..2..1....2..0..2..0....1..3..0..3....3..1..3..1
..2..2..0..2....0..2..0..2....2..2..0..2....2..3..1..2....3..2..3..2
..3..0..3..2....3..2..3..3....2..0..2..1....1..3..0..3....3..1..3..1