Number of (n+1)X(3+1) 0..3 arrays with the upper median minus the lower median of every 2X2 subblock differing from its horizontal and vertical neighbors by exactly one.

A237571

Number of (n+1)X(3+1) 0..3 arrays with the upper median minus the lower median of every 2X2 subblock differing from its horizontal and vertical neighbors by exactly one.