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Search: id:A126801
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| A126801 |
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a(n) = smallest integer which is coprime to n and is > A057237(n). |
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1
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| 2, 3, 4, 3, 6, 5, 8, 3, 4, 3, 12, 5, 14, 3, 4, 3, 18, 5, 20, 3, 4, 3, 24, 5, 6, 3, 4, 3, 30, 7, 32, 3, 4, 3, 6, 5, 38, 3, 4, 3, 42, 5, 44, 3, 4, 3, 48, 5, 8, 3, 4, 3, 54, 5, 6, 3, 4, 3, 60, 7, 62, 3, 4, 3, 6, 5, 68, 3, 4, 3, 72, 5, 74, 3, 4, 3, 8, 5, 80, 3
(list; graph; listen)
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OFFSET
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1,1
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COMMENT
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a(n) is also the smallest positive integer m, m > 1, which is coprime to n where (m-1) is not coprime to n.
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LINKS
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Leroy Quet, Home Page (listed in lieu of email address)
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EXAMPLE
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The integers which are coprime to 9 are 1,2,4,5,7,8,10,11,13,14,... Now 1 and 2, but not 3, are coprime to 9, so A057237(9) = 2. The smallest integer > 2 and coprime to 9 is 4. So a(9) = 4.
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MAPLE
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A020639 := proc(n) if n = 1 then 1 ; else min(op(numtheory[divisors](n) minus {1})) ; fi ; end: A057237 := proc(n) if n = 1 then 1 ; else A020639(n)-1 ; fi: end: A126801 := proc(n) local a; for a from A057237(n)+1 do if gcd(n, a) = 1 then RETURN(a) ; fi ; od: end: seq(A126801(n), n=1..80) ; - R. J. Mathar (mathar(AT)strw.leidenuniv.nl), Nov 01 2007
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CROSSREFS
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Cf. A057237.
Sequence in context: A138796 A064380 A126214 this_sequence A076945 A074792 A048276
Adjacent sequences: A126798 A126799 A126800 this_sequence A126802 A126803 A126804
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KEYWORD
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nonn
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AUTHOR
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Leroy Quet Feb 21 2007
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EXTENSIONS
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More terms from R. J. Mathar (mathar(AT)strw.leidenuniv.nl), Nov 01 2007
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