1/3 the number of n X 4 0..2 arrays with every element equal to exactly one or two of its horizontal and vertical neighbors.

A185554

1/3 the number of n X 4 0..2 arrays with every element equal to exactly one or two of its horizontal and vertical neighbors.

Terms

    a(0) =3a(1) =120a(2) =2530a(3) =58458a(4) =1317540a(5) =30132444a(6) =684657326a(7) =15594228288a(8) =354894362166

External references