Number of ways to reciprocally link elements of an n X n array either to themselves or to exactly one horizontal or antidiagonal neighbor.

A220557

Number of ways to reciprocally link elements of an n X n array either to themselves or to exactly one horizontal or antidiagonal neighbor.

Terms

    a(0) =1a(1) =5a(2) =64a(3) =3966a(4) =810778a(5) =665748170

External references