This is the number of positions that can be reached in n moves from the start, but which cannot be reached in fewer than n moves.
A puzzle in the Rubik cube family. The total number of distinct positions is 6912.
The tips are ignored. The antipode at distance 13 is the position with all 4 free edges flipped.
Table of n, a(n) for n=0..13.
Jaap Scherphuis, Puzzle Pages
Sequence in context: A004403 A084566 A208903 * A107035 A118885 A097392
Adjacent sequences: A079766 A079767 A079768 * A079770 A079771 A079772
N. J. A. Sloane, Feb 20 2003