Number of 5-colorings of an n-wheel graph.

Terms

a(0) =60a(1) =120a(2) =420a(3) =1200a(4) =3660a(5) =10920a(6) =32820a(7) =98400a(8) =295260a(9) =885720a(10) =2657220a(11) =7971600a(12) =23914860a(13) =71744520a(14) =215233620a(15) =645700800a(16) =1937102460a(17) =5811307320a(18) =17433922020a(19) =52301766000a(20) =156905298060a(21) =470715894120