OFFSET
0,2
COMMENTS
See under A090573.
EXAMPLE
a(1)=6 because the empty space in the center of the cube present in the assumed initial configuration can be replaced by any of the 6 adjacent cubes from the face centers in the first move.
PROG
moves = lambda p, shape: moves3d(p, shape)
start, shape = "123456789ABCD-EFGHIJKLMNOPQ", (3, 3, 3)
print(alst(start, shape, maxd=12)) # Michael S. Branicky, Dec 28 2020
CROSSREFS
KEYWORD
fini,hard,more,nonn
AUTHOR
Hugo Pfoertner, Jan 15 2004
EXTENSIONS
a(13)-a(16) from Michael S. Branicky, Dec 28 2020
STATUS
approved