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A090577
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Number of configurations of a variant of the 3-dimensional 3 X 3 X 3 sliding cube puzzle that require a minimum of n moves to be reached, starting with the empty space at one of the enclosing cube corners.
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2
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1, 3, 9, 24, 72, 174, 519, 1284, 3813, 9300, 27462, 66666, 195674, 470886, 1372946, 3280224, 9495005, 22487511, 64615934, 151714911
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OFFSET
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0,2
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COMMENTS
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The sliding cube 3 X 3 X 3 puzzle under consideration has a fixed central block and 25 movable blocks that can be shifted in the space between the enclosing holder frame and the central block. A description is given in US patents 3845959 and 6513808.
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LINKS
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Chih Chung Fang, Cubic Puzzle. US Patent 6513808, filed May 09, 2001
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EXAMPLE
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a(1)=3 because the empty space at one of the 6 corners in the assumed initial configuration can be replaced by any of the 3 adjacent cubes from the middle of the 3 edges meeting at the empty corner in the first move.
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PROG
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moves = lambda p, shape: moves3d(p, shape, fixed=13)
start, shape = "-123456789ABCDEFGHIJKLMNOPQ", (3, 3, 3)
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CROSSREFS
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KEYWORD
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fini,hard,more,nonn
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AUTHOR
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EXTENSIONS
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STATUS
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approved
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