Some initial facts
A couple of things are immediately clear.
- all moves keep the center cubies in their cubicles.
-
all moves of the Rubik’s cube puts corner cubies in corner cubicles
and edge cubies in edge cubicles.
There are 8! ways to arrange 8 the corner cubies.
Seven can be oriented independently, and the orientation of the eighth depends
on the preceding seven, giving 3
7
possibilities.
There are 12!/2 ways to arrange the 12 edges, since an odd permutation
of the corners implies an odd permutation of the edges as well.
Eleven edges can be flipped independently, with the flip of the twelfth depending
on the preceding ones, giving 2
11
possibilities.
All in all 2
12
∙ 3
8
∙ 12! ∙ 8! / 12 = .. = 2
27
∙ 3
14
∙ 5
3
∙ 7
2
∙ 11 = ~ 4 ∙ 10
19
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