1/6 the number of nX4 0..5 arrays with every element equal to exactly one or two of its horizontal and vertical neighbors.

A185537

1/6 the number of nX4 0..5 arrays with every element equal to exactly one or two of its horizontal and vertical neighbors.

Terms

    a(0) =6a(1) =1155a(2) =127570a(3) =17526450a(4) =2241330570a(5) =295044602325

External references