1/12 the number of (n+2) X 3 0..2 arrays with each 3 X 3 subblock containing three of each value.
A184378
1/12 the number of (n+2) X 3 0..2 arrays with each 3 X 3 subblock containing three of each value.
Terms
- a(0) =140a(1) =545a(2) =2174a(3) =9113a(4) =43295a(5) =212747a(6) =1096781a(7) =6045233a(8) =33958643a(9) =194694395a(10) =1141026791a(11) =6726497945a(12) =39885267065a(13) =237890735825
External references
- oeis: A184378