7751834609domain: NAppears in sequences1/4 the number of (n+1)X6 0..3 arrays with every 2X2 subblock having exactly two distinct clockwise edge differences.at n=5A2095501/4 the number of (n+1)X7 0..3 arrays with every 2X2 subblock having exactly two distinct clockwise edge differences.at n=4A209551