Number of Hamiltonian circuits within parallelograms of size 3 X n on the triangular lattice.

A339850

Number of Hamiltonian circuits within parallelograms of size 3 X n on the triangular lattice.

Terms

    a(0) =1a(1) =4a(2) =13a(3) =44a(4) =148a(5) =498a(6) =1676a(7) =5640a(8) =18980a(9) =63872a(10) =214944a(11) =723336a(12) =2434192a(13) =8191616a(14) =27566672a(15) =92768192a(16) =312186304a(17) =1050578720a(18) =3535439040a(19) =11897565568a(20) =40038044736a(21) =134737229824a(22) =453421769728

External references