Number of ways, counted up to symmetry, to build a contiguous building with n LEGO blocks of size 1 X 4 which is flat, i.e., with all blocks in parallel position and symmetric after a rotation by 180 degrees.
A123781
Number of ways, counted up to symmetry, to build a contiguous building with n LEGO blocks of size 1 X 4 which is flat, i.e., with all blocks in parallel position and symmetric after a rotation by 180 degrees.
Terms
- a(0) =1a(1) =1a(2) =5a(3) =7a(4) =41a(5) =65a(6) =384a(7) =649a(8) =3853a(9) =6745a(10) =40209a(11) =72334a(12) =431188a(13) =791144a(14) =4717533a(15) =8787824a(16) =52396271a(17) =98784645
External references
- oeis: A123781