Number of nX6 0..3 arrays with no more than floor(nX6/2) elements equal to at least one horizontal or antidiagonal neighbor, with new values introduced in row major 0..3 order.

A222876

Number of nX6 0..3 arrays with no more than floor(nX6/2) elements equal to at least one horizontal or antidiagonal neighbor, with new values introduced in row major 0..3 order.