Number of n X 4 arrays of occupancy after each element stays put or moves to some horizontal, diagonal or antidiagonal neighbor.

A221722

Number of n X 4 arrays of occupancy after each element stays put or moves to some horizontal, diagonal or antidiagonal neighbor.

Terms

    a(0) =21a(1) =3605a(2) =544757a(3) =81980587a(4) =12325049264

External references