A187670 T(n,k)=Number of (n+1)X(n+1) 0..k arrays with each 2X2 subblock nonsingular and the array of 2X2 subblock determinants symmetric about the diagonal and antidiagonal

6, 50, 24, 192, 550, 112, 512, 4044, 11282, 974, 1126, 17716, 174292, 612204, 9928, 2146, 56080, 1549398, 36461174, 65533922, 197152, 3760, 150166, 6839146, 835707780

Offset

1,1

Comments

Table starts

......6.......50......192.......512....1126...2146.3760

.....24......550.....4044.....17716...56080.150166

....112....11282...174292...1549398.6839146

....974...612204.36461174.835707780

...9928.65533922

.197152

Links

Table of n, a(n) for n=1..25.

Example

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

Crossrefs

Row 1 is A062801

Sequence in context: A187528 A187699 A212232 * A187462 A231270 A062801

Adjacent sequences: A187667 A187668 A187669 * A187671 A187672 A187673

Keyword

nonn,tabl

Author

R. H. Hardin Mar 12 2011

Status

approved