Number of ways to build a contiguous building with n LEGO blocks of size 2 X 3 on top of a fixed block of the same size so that the building is symmetric after a rotation by 180 degrees.

A123827

Number of ways to build a contiguous building with n LEGO blocks of size 2 X 3 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) =13a(2) =25a(3) =352a(4) =1006a(5) =15510a(6) =46928a(7) =744211a(8) =2479362

External references