Number of ways, counted up to symmetry, to build a contiguous building with n LEGO blocks of size 3 X 3 which is symmetric after a rotation by 180 degrees.
A123833
Number of ways, counted up to symmetry, to build a contiguous building with n LEGO blocks of size 3 X 3 which is symmetric after a rotation by 180 degrees.
Terms
- a(0) =1a(1) =1a(2) =9a(3) =22a(4) =317a(5) =980a(6) =13801a(7) =48756a(8) =660997a(9) =2505447
External references
- oeis: A123833