Number of (n+1)X4 0..2 arrays containing all values 0..2 with every 2X2 subblock having one or two distinct values, and new values 0..2 introduced in row major order.

A210090

Number of (n+1)X4 0..2 arrays containing all values 0..2 with every 2X2 subblock having one or two distinct values, and new values 0..2 introduced in row major order.