Number of ways to build a contiguous building with n LEGO blocks of size 1 X 3 on top of a fixed block of the same size so that the building is flat, i.e., with all blocks in parallel position.
A123776
Number of ways to build a contiguous building with n LEGO blocks of size 1 X 3 on top of a fixed block of the same size so that the building is flat, i.e., with all blocks in parallel position.
Terms
- a(0) =5a(1) =28a(2) =185a(3) =1287a(4) =9456a(5) =71167a(6) =549076a(7) =4300975a(8) =34154107a(9) =273998400a(10) =2217436152a(11) =18074303774a(12) =148232462372
External references
- oeis: A123776