68813532021domain: NAppears in sequencesNumber of (n+1) X 6 binary arrays with each element of every 2X2 subblock being the sum mod 2 of two others.at n=7A183841Number of (n+1) X 9 binary arrays with each element of every 2 X 2 subblock being the sum mod 2 of two others.at n=4A183844