Number of ways to seat 4 types of people in n labeled seats around a circle such that no two adjacent people are of the same type.

A218034

Number of ways to seat 4 types of people in n labeled seats around a circle such that no two adjacent people are of the same type.

Terms

    a(0) =1a(1) =4a(2) =12a(3) =24a(4) =84a(5) =240a(6) =732a(7) =2184a(8) =6564a(9) =19680a(10) =59052a(11) =177144a(12) =531444a(13) =1594320a(14) =4782972a(15) =14348904a(16) =43046724a(17) =129140160a(18) =387420492a(19) =1162261464a(20) =3486784404a(21) =10460353200a(22) =31381059612a(23) =94143178824a(24) =282429536484a(25) =847288609440

External references