A187669 Number of (n+1)X(n+1) 0..2 arrays with each 2X2 subblock nonsingular and the array of 2X2 subblock determinants symmetric about the diagonal and antidiagonal

50, 550, 11282, 612204, 65533922, 18950885038

Offset

1,1

Comments

Column 2 of A187670

Links

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

Example

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

Crossrefs

Sequence in context: A128954 A022147 A285044 * A366831 A160336 A231583

Adjacent sequences: A187666 A187667 A187668 * A187670 A187671 A187672

Keyword

nonn

Author

R. H. Hardin Mar 12 2011

Status

approved