4278774

Appears in sequences

• 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 90 degree rotation.at n=6A187525
• T(n,k)=Number of (n+1)X(n+1) 0..k arrays with each 2X2 subblock determinant nonzero and the array of 2X2 subblock determinants symmetric under 90 degree rotation.at n=27A187528