Number of ways to reciprocally link elements of an 4Xn array either to themselves or to exactly two horizontal, diagonal or antidiagonal neighbors.

A220728

Number of ways to reciprocally link elements of an 4Xn array either to themselves or to exactly two horizontal, diagonal or antidiagonal neighbors.

Terms

    a(0) =1a(1) =8a(2) =126a(3) =2586a(4) =52189a(5) =1071230a(6) =21914482a(7) =449023031a(8) =9196824619a(9) =188399767218

External references