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 225. Here positions differing by rotations are considered the same.
Table of n, a(n) for n=0..16.
Jaap Scherphuis, Puzzle Pages
Sequence in context: A226084 A294861 A161664 * A080555 A024924 A023668
Adjacent sequences: A080544 A080545 A080546 * A080548 A080549 A080550
N. J. A. Sloane, Feb 21 2003