A187460 Number of (n+1)X(n+1) 0..3 arrays with all the 2X2 subblocks nonsingular and the array of 2X2 subblock determinants symmetric

192, 13726, 5098224, 3387715318, 19708386669940, 150657364854061134

Offset

1,1

Comments

Column 3 of A187462

Links

Table of n, a(n) for n=1..6.

Example

Some solutions for 5X5
..0..2..2..0..1....0..2..2..0..1....0..2..2..0..1....0..2..2..0..2
..2..2..0..2..1....2..2..0..2..0....2..2..0..2..1....2..2..0..2..2
..2..0..1..0..1....2..0..3..0..2....2..0..3..0..3....2..0..2..0..1
..0..2..0..1..3....0..2..0..2..1....0..2..0..2..1....0..2..0..2..0
..1..2..1..2..3....1..2..2..1..0....1..1..3..3..3....2..1..1..3..1

Crossrefs

Sequence in context: A290178 A282208 A154308 * A200209 A205760 A338532

Adjacent sequences: A187457 A187458 A187459 * A187461 A187462 A187463

Keyword

nonn

Author

R. H. Hardin Mar 10 2011

Status

approved