Number of ways to build a contiguous building with n LEGO blocks of size 1 X 6 on top of a fixed block of the same size so that the building is symmetric after a rotation by 180 degrees.

A123799

Number of ways to build a contiguous building with n LEGO blocks of size 1 X 6 on top of a fixed block of the same size so that the building is symmetric after a rotation by 180 degrees.

Terms

    a(0) =1a(1) =22a(2) =43a(3) =1039a(4) =3136a(5) =81773a(6) =267670a(7) =7192059

External references