Number of (n+1)X(n+1) 0..3 arrays with every 2X2 subblock having one, two or four distinct values, and new values 0..3 introduced in row major order.

A210053

Number of (n+1)X(n+1) 0..3 arrays with every 2X2 subblock having one, two or four distinct values, and new values 0..3 introduced in row major order.