Invitation: celebrating 50 years of OEIS, 250000 sequences, and Sloane's 75th, there will be a conference at DIMACS, Rutgers, Oct 9-10 2014.
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 4961250. Here we consider a move to be a turn of a disc by any amount.
Table of n, a(n) for n=0..19.
Jaap Scherphuis, Puzzle Pages
Sequence in context: A211295 A211289 A211292 * A211282 A211298 A138574
Adjacent sequences: A079854 A079855 A079856 * A079858 A079859 A079860
N. J. A. Sloane, Feb 21 2003