Number of ways, counted up to symmetry, to build a contiguous building with n LEGO blocks of size 1 X 4 which is symmetric after a rotation by 180 degrees.
A123779
Number of ways, counted up to symmetry, to build a contiguous building with n LEGO blocks of size 1 X 4 which is symmetric after a rotation by 180 degrees.
Terms
- a(0) =1a(1) =1a(2) =21a(3) =67a(4) =849a(5) =3185a(6) =39868a(7) =162562a(8) =2027829
External references
- oeis: A123779