Number of (n+1)X(n+1) 0..3 symmetric matrices containing all values 0..3 with every 2X2 subblock having two, three or four distinct values, and new values 0..3 introduced in lower triangle row major order.

A210824

Number of (n+1)X(n+1) 0..3 symmetric matrices containing all values 0..3 with every 2X2 subblock having two, three or four distinct values, and new values 0..3 introduced in lower triangle row major order.