Number of ways to build a contiguous building with n LEGO blocks of size 2 X 4 on top of a fixed block of the same size so that the building is symmetric after a rotation by 180 degrees.

A123831

Number of ways to build a contiguous building with n LEGO blocks of size 2 X 4 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) =2a(1) =24a(2) =88a(3) =1079a(4) =5563a(5) =74597a(6) =412309a(7) =5633649

External references