Number of 2n X 4 0..2 arrays with values 0..2 introduced in row major order and each element equal to exactly two horizontal and vertical neighbors.
A198279
Number of 2n X 4 0..2 arrays with values 0..2 introduced in row major order and each element equal to exactly two horizontal and vertical neighbors.
Terms
- a(0) =1a(1) =4a(2) =14a(3) =52a(4) =190a(5) =700a(6) =2574a(7) =9476a(8) =34878a(9) =128396a(10) =472654a(11) =1739988a(12) =6405438a(13) =23580508a(14) =86807566a(15) =319567268a(16) =1176432574a(17) =4330837036a(18) =15943242574a(19) =58692346740a(20) =216065933246a(21) =795410139132
External references
- oeis: A198279