A187700 Number of 4X4 0..n arrays with each 2X2 subblock determinant nonzero and the array of 2X2 subblock determinants symmetric under horizontal and vertical reflection.

104, 7954, 87258, 692410, 2363474, 10839282, 23999702, 69386216, 148926738

Offset: 1

Author

R. H. Hardin Mar 12 2011

Keywords

• nonn

Comments

Row 3 of A187699

Examples

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