152332domain: NAppears in sequencesNumber of (n+1) X 3 binary arrays with every 2 X 2 subblock commuting with each of its horizontal and vertical 2 X 2 subblock neighbors.at n=21A186455a(n) is the numerator of (120*n^2 + 151*n + 47)/(512*n^4 + 1024*n^3 + 712*n^2 + 194*n + 15).at n=35A374580