Number of n X 2 arrays of occupancy after each element moves to some horizontal, diagonal or antidiagonal neighbor, without move-in move-out left turns.
A221652
Number of n X 2 arrays of occupancy after each element moves to some horizontal, diagonal or antidiagonal neighbor, without move-in move-out left turns.
Terms
- a(0) =1a(1) =4a(2) =12a(3) =40a(4) =136a(5) =460a(6) =1556a(7) =5264a(8) =17808a(9) =60244a(10) =203804a(11) =689464a(12) =2332440a(13) =7890588a(14) =26693668a(15) =90304032a(16) =305496352a(17) =1033486756a(18) =3496260652a(19) =11827765064a(20) =40013042600a(21) =135363153516a(22) =457930268212
External references
- oeis: A221652