A187696
Number of (n+1)X(n+1) 0..1 arrays with each 2X2 subblock determinant nonzero and the array of 2X2 subblock determinants symmetric under horizontal and vertical reflection.
Original entry on oeis.org
6, 0, 104, 0, 9350, 0, 4280018, 0, 9966761956, 0, 118224466422070, 0, 7149599148533804130, 0, 2205540801307910506482568, 0
Offset: 1
Some solutions for 4X4
..1..0..1..1....1..1..0..1....1..1..1..1....1..1..0..1....0..1..0..1
..1..1..0..1....1..0..1..1....1..0..1..0....1..0..1..0....1..0..1..0
..1..0..1..0....0..1..0..1....1..1..0..1....0..1..0..1....0..1..0..1
..1..1..0..1....1..0..1..1....1..0..1..0....1..1..1..0....1..1..1..0
A187697
Number of (n+1)X(n+1) 0..2 arrays with each 2X2 subblock determinant nonzero and the array of 2X2 subblock determinants symmetric under horizontal and vertical reflection.
Original entry on oeis.org
50, 8, 7954, 1548, 15128848, 454640, 231192094416
Offset: 1
Some solutions for 4X4
..0..2..0..2....2..0..2..0....2..2..0..2....1..2..1..0....1..2..0..2
..1..1..1..1....1..2..0..2....1..0..1..0....0..1..0..1....2..2..1..2
..0..1..0..1....2..0..2..0....0..2..0..2....1..0..1..0....1..2..0..2
..2..1..2..0....1..2..1..2....1..0..1..0....0..1..2..1....2..2..1..0
A187698
Number of (n+1)X(n+1) 0..3 arrays with each 2X2 subblock determinant nonzero and the array of 2X2 subblock determinants symmetric under horizontal and vertical reflection.
Original entry on oeis.org
192, 74, 87258, 22738, 1089964504
Offset: 1
Some solutions for 4X4
..2..2..1..2....0..3..0..3....1..2..2..2....2..3..1..0....0..1..0..1
..3..0..3..0....2..1..2..1....2..0..2..0....1..3..0..3....3..1..3..1
..2..2..0..2....0..2..0..2....2..2..0..2....2..3..1..2....3..2..3..2
..3..0..3..2....3..2..3..3....2..0..2..1....1..3..0..3....3..1..3..1
A187700
Number of 4X4 0..n arrays with each 2X2 subblock determinant nonzero and the array of 2X2 subblock determinants symmetric under horizontal and vertical reflection.
Original entry on oeis.org
104, 7954, 87258, 692410, 2363474, 10839282, 23999702, 69386216, 148926738
Offset: 1
Some n=3 solutions for 4X4
..0..2..0..2....0..3..0..3....2..1..2..1....0..1..0..1....0..1..3..2
..3..1..3..0....1..0..1..3....2..3..2..3....1..3..1..3....2..0..1..0
..0..2..0..2....0..1..0..1....3..1..3..1....1..2..1..2....0..1..0..2
..3..2..3..0....3..0..3..2....2..2..2..2....1..1..1..1....2..2..1..2
Showing 1-4 of 4 results.
Comments