Number of n X 2 arrays of occupancy after each element stays put or moves to some horizontal or vertical neighbor, without consecutive moves in the same direction.
A221821
Number of n X 2 arrays of occupancy after each element stays put or moves to some horizontal or vertical neighbor, without consecutive moves in the same direction.
Terms
- a(0) =3a(1) =31a(2) =252a(3) =2113a(4) =17684a(5) =147920a(6) =1237439a(7) =10351593a(8) =86594795a(9) =724396370a(10) =6059833949a(11) =50692672540a(12) =424062286786
External references
- oeis: A221821