Number of nX4 0..2 arrays with every 1 immediately preceded by 0 to the left or above, no 0 immediately preceded by a 0, and every 2 immediately preceded by 0 1 to the left or above.
A203177
Number of nX4 0..2 arrays with every 1 immediately preceded by 0 to the left or above, no 0 immediately preceded by a 0, and every 2 immediately preceded by 0 1 to the left or above.
Terms
- a(0) =2a(1) =4a(2) =17a(3) =59a(4) =205a(5) =724a(6) =2466a(7) =8948a(8) =30945a(9) =108083a(10) =382615a(11) =1333850a(12) =4692643a(13) =16441939a(14) =57654309a(15) =202490869a(16) =709321155a(17) =2489832932a(18) =8732839148a(19) =30624223891a(20) =107449317301a(21) =376820699674
External references
- oeis: A203177