Number of nX5 0..3 arrays with exactly floor(nX5/2) elements equal to at least one horizontal, vertical or antidiagonal neighbor, with new values introduced in row major 0..3 order.

A222721

Number of nX5 0..3 arrays with exactly floor(nX5/2) elements equal to at least one horizontal, vertical or antidiagonal neighbor, with new values introduced in row major 0..3 order.

Terms

    a(0) =20a(1) =6524a(2) =2807505a(3) =1928517786a(4) =662075303107

External references