Number of n X 2 arrays of occupancy after each element moves to some horizontal or vertical neighbor, without move-in move-out left turns.
A221673
Number of n X 2 arrays of occupancy after each element moves to some horizontal or vertical neighbor, without move-in move-out left turns.
Terms
- a(0) =1a(1) =5a(2) =27a(3) =139a(4) =715a(5) =3666a(6) =18787a(7) =96249a(8) =493063a(9) =2525780a(10) =12938520a(11) =66278434a(12) =339515341a(13) =1739187492a(14) =8909090065a(15) =45637335102a(16) =233779915777
External references
- oeis: A221673