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 configurations is 440. Here we count "configurations", ignoring the colors of the pieces.
Table of n, a(n) for n=0..12.
Jaap Scherphuis, Puzzle Pages
Sequence in context: A001106 A023551 A022787 * A079771 A297225 A258438
Adjacent sequences: A079767 A079768 A079769 * A079771 A079772 A079773
N. J. A. Sloane, Feb 20 2003