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A048200
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Minimal length pair-exchange / set-rotate sequence to reverse n distinct ordered elements.
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2
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OFFSET
| 1,3
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COMMENTS
| "Rotate" is always a left-rotate (moves leftmost element to the right end) and "Exchange" is always a pair-exchange of the two leftmost elements.
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EXAMPLE
| a(4) = 4 since "xrrx" is the shortest sequence reversing "ABCD". Explicitly, (begin) ABCD, (x)-> BACD, (r)-> ACDB, (r) -> CDBA, (x)-> DCBA.
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CROSSREFS
| Sequence in context: A056392 A080149 A128513 * A064513 A058201 A000947
Adjacent sequences: A048197 A048198 A048199 * A048201 A048202 A048203
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KEYWORD
| nonn,nice,more
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AUTHOR
| Tony Bartoletti (azb(AT)comcast.net)
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EXTENSIONS
| 55 added by Tony Bartoletti, Feb 22 2011
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