213959648565domain: NAppears in sequences1/4 the number of (n+1)X5 0..3 arrays with every 2X2 subblock having one or four distinct clockwise edge differences.at n=4A2098541/4 the number of (n+1)X6 0..3 arrays with every 2X2 subblock having one or four distinct clockwise edge differences.at n=3A209855