Number of ways, counted up to symmetry, to build a contiguous building with n LEGO blocks of size 2 X 2 which is symmetric after a rotation by 180 degrees.
A123819
Number of ways, counted up to symmetry, to build a contiguous building with n LEGO blocks of size 2 X 2 which is symmetric after a rotation by 180 degrees.
Terms
- a(0) =1a(1) =1a(2) =5a(3) =8a(4) =65a(5) =126a(6) =1023a(7) =2187a(8) =17585a(9) =39606a(10) =315326a(11) =737302
External references
- oeis: A123819