154561domain: NAppears in sequencesNumber of (n+1)X(n+1) 0..2 arrays with every 2X2 subblock singular.at n=2A185512Number of (n+1) X 4 0..2 arrays with every 2 X 2 subblock singular.at n=2A185515T(n,k)=Number of (n+1)X(k+1) 0..2 arrays with every 2X2 subblock singular.at n=12A185521