A187672 Number of 4X4 0..n arrays with each 2X2 subblock nonsingular and the array of 2X2 subblock determinants symmetric about the diagonal and antidiagonal.

112, 11282, 174292, 1549398, 6839146, 32368980, 88344978, 268011840

Offset: 1

Author

R. H. Hardin Mar 12 2011

Keywords

• nonn

Comments

Row 3 of A187670

Examples

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