Number of n X 2 arrays of occupancy after each element moves to some horizontal or vertical neighbor, without move-in move-out straight through or left turns.
A221795
Number of n X 2 arrays of occupancy after each element moves to some horizontal or vertical neighbor, without move-in move-out straight through or left turns.
Terms
- a(0) =1a(1) =5a(2) =12a(3) =39a(4) =112a(5) =338a(6) =1001a(7) =2985a(8) =8881a(9) =26440a(10) =78707a(11) =234288a(12) =697446a(13) =2076121a(14) =6180257a(15) =18397277a(16) =54765156a(17) =163024591a(18) =485291776a(19) =1444615370a(20) =4300329993a(21) =12801215625a(22) =38106643849a(23) =113435806112a(24) =337675564859
External references
- oeis: A221795