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Search: id:A136094
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| A136094 |
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a(n) is the shortest substring containing all the permutations of {1,...,n} as (not necessarily adjacent) substrings. |
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2
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| 1, 121, 1232123, 1234321234321, 123454321234543212345, 1234565432123456543212345654321, 1234567654321234567654321234567654321234567
(list; graph; listen)
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OFFSET
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1,2
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COMMENT
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In case of a tie we pick the earliest example.
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REFERENCES
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P. J. Koutas and T. C. Hu, Shortest String Containing All Permutations, Discrete Mathematics, Vol. 11, 1975, pp. 125-132.
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LINKS
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Hu, T. C., and Koutas, P. J., Shortest Substing.
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EXAMPLE
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a(4)=1234321234321 because it contains all the permutation 1234((1234)321234321), 1243((12)3(43)21234321), 1324((1)2(3)4321(2)3(4)321), 1342((1)2(34)3(2)1234321), 1423, 1432, 2134, 2143, 2314, etc. The brackets indicate where the permutation is present.
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CROSSREFS
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Adjacent sequences: A136091 A136092 A136093 this_sequence A136095 A136096 A136097
Sequence in context: A135825 A082215 A123179 this_sequence A053885 A068490 A077735
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KEYWORD
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nonn
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AUTHOR
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Aniruddha Das (hi.annie.pal(AT)gmail.com), May 10 2008
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EXTENSIONS
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Edited by njas, May 16 2008
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