

A080601


Number of positions in which the 3 X 3 X 3 Rubik's cube puzzle can be after exactly n moves, where a move is either a quarterturn or a halfturn.


27



1, 18, 243, 3240, 43239, 574908, 7618438, 100803036, 1332343288, 17596479795, 232248063316, 3063288809012, 40374425656248, 531653418284628, 6989320578825358, 91365146187124313
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OFFSET

0,2


COMMENTS

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.
The total number of positions is (8!*12!/2)*(2^12/2)*(3^8/3) = 43252003274489856000.  Jerry Bryan, Mar 03 2003
Relationship with A080583: 243 = 262  18  1, 3240 = 3502  262, 43239 = 46741  3502, ...


REFERENCES

Robert G. Bryan (Jerry Bryan), posting to Cube Lovers List, Jul 10, 1998.
Rokicki, Tomas. Thirty years of computer cubing: The search for God's number. 2014. Reprinted in "Barrycades and Septoku: Papers in Honor of Martin Gardner and Tom Rogers", ed. Thane Plambeck and Tomas Rokicki, MAA Press, 2020, pp. 7998. See Table 9.4.
Rokicki, T., Kociemba, H., Davidson, M., & Dethridge, J. (2014). The diameter of the rubik's cube group is twenty. SIAM REVIEW, 56(4), 645670. See Table 5.1.


LINKS

Table of n, a(n) for n=0..15.
Alan Bawden, Cube Lovers Archive, Part 25
Jerry Bryan, God's Algorithm...
Mark Longridge, God's Algorithm Calculations for Rubik's Cube...
Tomas Rokicki, God's Algorithm out to 13f*
Tomas Rokicki, God's Number is 20
T. Rokicki, Twentytwo moves suffice for Rubik's Cube, Math. Intell. 32 (1) (2010) 3340.
T. Rokicki, 15f* in the Face Turn Metric.
T. Rokicki, God's Algorithm out to 14f*


CROSSREFS

Cf. A080638, A005452, A080602.
Sequence in context: A181379 A080629 A053540 * A333298 A016186 A081203
Adjacent sequences: A080598 A080599 A080600 * A080602 A080603 A080604


KEYWORD

nonn,fini


AUTHOR

N. J. A. Sloane, Feb 25 2003


EXTENSIONS

a(11) (from Jerry Bryan, 2006) and a(12) (from Tom Rokicki, 2009) added by Herbert Kociemba, Jun 24 2009
a(13) added by Tomas Rokicki, Jul 25 2009
a(14) (from Thomas Scheunemann) and a(15) (from Morley Davidson, John Dethridge, Herbert Kociemba, and Tomas Rokicki) added by Tomas Rokicki, Jul 29 2010
Name edited by Charles R Greathouse IV, Jan 19 2016


STATUS

approved



