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

A123842

Number of ways to build a contiguous building with n LEGO blocks of size 4 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) =1a(1) =21a(2) =41a(3) =903a(4) =2641a(5) =62831a(6) =195929a(7) =4771243

External references