Number of (n+1)X(n+1) 0..3 arrays with every 2X2 subblock having equal diagonal elements or equal antidiagonal elements, and new values 0..3 introduced in row major order.

A204564

Number of (n+1)X(n+1) 0..3 arrays with every 2X2 subblock having equal diagonal elements or equal antidiagonal elements, and new values 0..3 introduced in row major order.