The Group Cs (a)

Silviu Radu managed to do a complete analysis of the 18,345,885,696 different cubes of this subgroup which has the highest number of 20f*-maneuvers from all symmetric subgroups. Here the the table with the distances, the average distance is 17.87:

Distance
Number
Distance
Number
0f
1
11f
324,496
1f
4
12f
1,019,512
2f
13
13f
4,128,898
3f
48
14f
20,060,486
4f
159
15f
103,107,447
5f
464
16f
607,357,293
6f
1,554
17f
3,601,456,840
7f
4,758
18f
11,082,306,785
8f
13,810
19f
2,925,751,099
9f
40,353
20f
197,592
10f
114,084

Up to M-symmetry there are 2,292,846,080 cubes which exactly have this symmetry and of these there are 23793 cubes which need 20 moves. All other cubes can be solved in 19 moves or less. 7391 out of these 23793 cubes with 20 moves have antisymmetry. Up to M-symmetry and M-antisymmetry it are 15592 20f*-cubes, which are included in the file 20moves.zip. We display only some examples of this huge symmetry class here.

The next table gives the number of cubes up to M-symmetry which exactly have C(a)-symmetry. To compute this number we used the following identity, where C(a)Total is the table above and the right side hold the tables for the number of cubes mod M with exactly the symmetry of the subgroups of C(a), which are all known except for Cs (a) itself.

C(a)Total = 8 C(a) + 4 C2h (a) + 4 C2v (b) + 8 C2v (a2) + 6 D2h (face) + 2 D2h (edge) +
4 D2d (edge) + 2 C4h + 4 C4v + 3 D4h + 2 Th + Oh

The average maneuver length also is 17.87:

Distance
Number
Distance
Number
0f
0
11f
40,016
1f
0
12f
125,984
2f
1
13f
513,072
3f
4
14f
2,501,038
4f
17
15f
12,877,423
5f
48
16f
75,889,571
6f
176
17f
450,107,871
7f
555
18f
1,385,122,357
8f
1,662
19f
365,623,453
9f
4,977
20f
23,793
10f
14,062
Name
shortest maneuver with exactly this symmetry
Generator
F2 R2 (2f*)
Name
Generator
L R2 D' L B2 F2 R' B R2 F2 L D' L R2 B2 R' (16f*)
Name
Generator
D2 B2 U2 B2 D' F' L2 F R' B2 R B' U2 B U' (15f*)
Name
Generator
R2 B2 R' D B F2 D' B2 R2 B' R' D U' L' U F2 U' (17f*)
Name
Generator
R' B' R' B D B2 F2 U' L2 F2 L D' F' D2 F' L' (16f*)
Name
Generator
U2 B' R2 D2 F2 U' L' U2 F2 D2 U2 R2 F' R' F D' U' (17f*)
Name
Generator
R B2 F U' F L' B' R2 D U' L B' L' U' L' U (16f*)

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© 2017  Herbert Kociemba