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 2160.
Table of n, a(n) for n=0..6.
Jaap Scherphuis, Puzzle Pages
Sequence in context: A073390 A069021 * A079785 A225977 A002697 A026761
Adjacent sequences: A079760 A079761 A079762 * A079764 A079765 A079766
N. J. A. Sloane, Feb 20 2003