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Search: id:A048669
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| A048669 |
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Jacobsthal function: maximal distance between integers relatively prime to n. |
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+0
9
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| 1, 2, 2, 2, 2, 4, 2, 2, 2, 4, 2, 4, 2, 4, 3, 2, 2, 4, 2, 4, 3, 4, 2, 4, 2, 4, 2, 4, 2, 6, 2, 2, 3, 4, 3, 4, 2, 4, 3, 4, 2, 6, 2, 4, 3, 4, 2, 4, 2, 4, 3, 4, 2, 4, 3, 4, 3, 4, 2, 6, 2, 4, 3, 2, 3, 6, 2, 4, 3, 6, 2, 4, 2, 4, 3, 4, 3, 6, 2, 4, 2, 4, 2, 6, 3, 4, 3, 4, 2, 6, 3, 4, 3, 4, 3, 4, 2, 4, 3, 4, 2, 6, 2, 4, 5
(list; graph; listen)
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OFFSET
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1,2
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COMMENT
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Differs from A070194 by 1 at the primes. - T. D. Noe, Mar 21 2007
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REFERENCES
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E. Jacobsthal, Uber Sequenzen ganzer Zahlen, von denen keine zu n teilerfremd ist, I, II, III. Norske Videnskabsselskab Forhdl., 33, 1960, 117-139
P. Erdos, On the integers relatively prime to n and on a number theoretic function considered by Jacobsthal. Math. Scand., 10, 1962, 163-170
H. Iwaniec, On the problem of Jacobsthal. Demo. Math., 11, 1978, 225-231
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LINKS
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T. D. Noe, Table of n, a(n) for n=1..10000
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EXAMPLE
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a(6)=4 because the gap between 1 and 5, both being relatively prime to 6, is maximal, and 5-1 = 4.
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CROSSREFS
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Cf. A048670. Essentially same as A049298. See A132468 for another version.
Cf. A070971.
Adjacent sequences: A048666 A048667 A048668 this_sequence A048670 A048671 A048672
Sequence in context: A122066 A053238 A058263 this_sequence A034444 A073180 A127973
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KEYWORD
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nonn,easy,nice
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AUTHOR
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Jan Kristian Haugland (jankrihau(AT)hotmail.com)
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