Number of ways, counted up to symmetry, to build a contiguous building with n LEGO blocks of size 1 X 3 which is symmetric after a rotation by 180 degrees.
A123771
Number of ways, counted up to symmetry, to build a contiguous building with n LEGO blocks of size 1 X 3 which is symmetric after a rotation by 180 degrees.
Terms
- a(0) =1a(1) =2a(2) =12a(3) =45a(4) =264a(5) =1128a(6) =6991a(7) =32202a(8) =202856a(9) =973242a(10) =6204349
External references
- oeis: A123771