174401424domain: NAppears in sequences1/4 the number of (n+1)X5 0..3 arrays with every 2X2 subblock having exactly two distinct clockwise edge differences.at n=5A2095491/4 the number of (n+1)X7 0..3 arrays with every 2X2 subblock having exactly two distinct clockwise edge differences.at n=3A209551