1/5 the number of nX4 0..4 arrays with every element equal to exactly one or two of its horizontal and vertical neighbors.
A185820
1/5 the number of nX4 0..4 arrays with every element equal to exactly one or two of its horizontal and vertical neighbors.
Terms
- a(0) =5a(1) =656a(2) =49036a(3) =4443292a(4) =378212944a(5) =32995092992
External references
- oeis: A185820