A187461 Number of (n+1)X(n+1) 0..4 arrays with all the 2X2 subblocks nonsingular and the array of 2X2 subblock determinants symmetric.

512, 84048, 100936174, 216668424092, 7540469990506332

Offset: 1

Author

R. H. Hardin Mar 10 2011

Keywords

• nonn

Comments

Column 4 of A187462

Examples

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