A187704 - OEIS

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

%S 170,93476,2904,4225652,12898

%N Number of (n+1)X(n+1) 0..5 arrays with each 2X2 subblock off diagonal and antidiagonal nonsingular and the array of 2X2 subblock determinants antisymmetric about the diagonal and antidiagonal

%C Column 5 of A187705

%e Some solutions for 4X4

%e ..3..2..0..0....0..0..1..0....2..2..4..0....1..1..0..0....2..2..4..0

%e ..3..2..2..4....3..2..1..0....5..5..5..0....1..1..2..4....2..2..2..0

%e ..5..2..2..2....2..2..1..2....0..2..2..2....3..1..2..3....0..2..2..2

%e ..0..0..2..2....4..4..1..2....0..5..0..0....0..0..2..3....0..4..2..2

%K nonn

%O 1,1

%A _R. H. Hardin_ Mar 12 2011