Number of ways to build a contiguous building with n LEGO blocks of size 1 X 4 on top of a fixed block of the same size so that the building is flat, i.e., with all blocks in parallel position.
A123784
Number of ways to build a contiguous building with n LEGO blocks of size 1 X 4 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) =7a(1) =55a(2) =511a(3) =5000a(4) =51674a(5) =547204a(6) =5940045a(7) =65472189a(8) =731569499a(9) =8258444996a(10) =94045306573
External references
- oeis: A123784