Number of ways to build a contiguous building with n LEGO blocks of size 1 X 8 on top of a fixed block of the same size so that the building is flat, i.e., with all blocks in parallel position and symmetric after a rotation by 180 degrees.
A123817
Number of ways to build a contiguous building with n LEGO blocks of size 1 X 8 on top of a fixed block of the same size so that the building is flat, i.e., with all blocks in parallel position and symmetric after a rotation by 180 degrees.
Terms
- a(0) =1a(1) =5a(2) =9a(3) =51a(4) =131a(5) =807a(6) =2129a(7) =13967a(8) =39701a(9) =265152a(10) =781478a(11) =5287858a(12) =16094282a(13) =110147280a(14) =342365511a(15) =2360643691
External references
- oeis: A123817