A187631 Number of (n+1)X(n+1) 0..3 arrays with the array of 2X2 subblock determinants antisymmetric under horizontal and vertical reflection and each non-centerline 2X2 subblock nonsingular.

64, 2924, 14044, 31903442, 33869160

Offset: 1

Author

R. H. Hardin Mar 12 2011

Keywords

• nonn

Comments

Column 3 of A187633

Examples

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