Number of 2nX2n 0..2 arrays with values 0..2 introduced in row major order and each element equal to exactly two horizontal and vertical neighbors.
A198278
Number of 2nX2n 0..2 arrays with values 0..2 introduced in row major order and each element equal to exactly two horizontal and vertical neighbors.
Terms
- a(0) =1a(1) =4a(2) =100a(3) =8784a(4) =2823604a(5) =3337609528
External references
- oeis: A198278