A161222 - cp's OEIS frontend

A161222 Consider necklaces with n beads, each of one of four colors (say C1, C2, C3, C4), where the n segments of cord between the beads are each colored red or green; a(n) is the number of different necklaces under the action of the dihedral group D_{2n}.

n	a(n)
0	1
1	8
2	30
3	120
4	618
5	3536
6	22668
7	151848
8	1054986
9	7472984
10	53737896
11	390582648
12	2863716060
13	21145502960
14	157076310324
15	1172820793824
16	8796118712586
17	66229473393728
18	500400163666188
19	3792505486235544
20	28823039252629512
21	219604100410657136
22	1676976747053723292

[1, 8, 30, 120, 618, 3536, 22668, 151848, 1054986, 7472984, 53737896, 390582648, 2863716060, 21145502960, 157076310324, 1172820793824, 8796118712586, 66229473393728, 500400163666188, 3792505486235544, 28823039252629512, 219604100410657136, 1676976747053723292]

cp's OEIS Frontend

A161222 Consider necklaces with n beads, each of one of four colors (say C1, C2, C3, C4), where the n segments of cord between the beads are each colored red or green; a(n) is the number of different necklaces under the action of the dihedral group D_{2n}.

Table of values

List of values