Number of cyclic change-ringing sequences of length n for 4 bells.

Terms

a(0) =1a(1) =4a(2) =6a(3) =6a(4) =0a(5) =4a(6) =28a(7) =106a(8) =282a(9) =660a(10) =1496a(11) =3344a(12) =7176a(13) =14616a(14) =27560a(15) =47672a(16) =76092a(17) =112416a(18) =148808a(19) =166960a(20) =148848a(21) =98560a(22) =43424a(23) =10792