Number of 2n X 4 0..4 arrays with values 0..4 introduced in row major order and each element equal to exactly two horizontal and vertical neighbors.
A198247
Number of 2n X 4 0..4 arrays with values 0..4 introduced in row major order and each element equal to exactly two horizontal and vertical neighbors.
Terms
- a(0) =1a(1) =5a(2) =40a(3) =485a(4) =6528a(5) =90641a(6) =1268648a(7) =17794141a(8) =249720000a(9) =3505037833a(10) =49198133832a(11) =690571872597
External references
- oeis: A198247