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Search: id:A165960
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| A165960 |
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Number of permutations of length n without modular 3-sequences |
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+0
4
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| 3, 20, 100, 612, 4389, 35688, 325395, 3288490, 36489992, 441093864, 5770007009, 81213878830
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OFFSET
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3,1
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COMMENT
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Modular 3-sequences are of the following form: i,i+1,i+2, where arithmetic is modulo n.
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FORMULA
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Let b(n) be the sequence A165961. Then this sequence a(n)=n(b(n)).
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EXAMPLE
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For n=3 the a(3)=3 solutions are (0,2,1), (1,0,2) and (2,1,0).
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CROSSREFS
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Cf. A002628, A165961, A165962.
Sequence in context: A092786 A015529 A000948 this_sequence A074831 A000917 A025535
Adjacent sequences: A165957 A165958 A165959 this_sequence A165961 A165962 A165963
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KEYWORD
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nonn
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AUTHOR
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Isaac E. Lambert (lamberti09(AT)mail.wlu.edu), Oct 01 2009
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