A187455 - OEIS

%I #4 Mar 31 2012 12:36:08

%S 256,38464,34166592,99952737952,1694940245504992,98104220374911288448

%N Number of (n+1)X(n+1) 0..3 arrays with the array of 2X2 subblock determinants symmetric

%C Column 3 of A187457

%e Some solutions for 5X5

%e ..0..0..0..0..0....0..0..0..0..0....0..0..0..0..0....0..0..0..0..0

%e ..0..0..0..0..0....0..0..0..0..0....0..0..0..0..0....0..0..0..0..0

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

%e ..0..0..0..0..0....0..0..0..0..0....0..0..0..0..0....0..0..0..0..0

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

%K nonn

%O 1,1

%A _R. H. Hardin_ Mar 10 2011