A187631 - OEIS

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

%S 64,2924,14044,31903442,33869160

%N Number of (n+1)X(n+1) 0..3 arrays with the array of 2X2 subblock determinants antisymmetric under horizontal and vertical reflection and each non-centerline 2X2 subblock nonsingular

%C Column 3 of A187633

%e Some solutions for 4X4

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

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

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

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

%K nonn

%O 1,1

%A _R. H. Hardin_ Mar 12 2011