Number of ways to reciprocally link elements of an nX7 array either to themselves or to exactly two horizontal, vertical or antidiagonal neighbors.

A220687

Number of ways to reciprocally link elements of an nX7 array either to themselves or to exactly two horizontal, vertical or antidiagonal neighbors.

Terms

    a(0) =1a(1) =1081a(2) =362057a(3) =128995678a(4) =42362190063

External references