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 96. Here positions differing by rotations are considered the same.
Table of n, a(n) for n=0..12.
Jaap Scherphuis, Puzzle Pages
Cf. A010928, A080560-A080564.
Sequence in context: A037221 A182537 A212061 * A151866 A057587 A213036
Adjacent sequences: A080557 A080558 A080559 * A080561 A080562 A080563
N. J. A. Sloane, Feb 21 2003