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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
0

%I #4 Mar 31 2012 12:36:09

%S 192,74,87258,22738,1089964504

%N 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

%C Column 3 of A187699

%e Some solutions for 4X4

%e ..2..2..1..2....0..3..0..3....1..2..2..2....2..3..1..0....0..1..0..1

%e ..3..0..3..0....2..1..2..1....2..0..2..0....1..3..0..3....3..1..3..1

%e ..2..2..0..2....0..2..0..2....2..2..0..2....2..3..1..2....3..2..3..2

%e ..3..0..3..2....3..2..3..3....2..0..2..1....1..3..0..3....3..1..3..1

%K nonn

%O 1,1

%A _R. H. Hardin_ Mar 12 2011