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A091456
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Least number k such that n * phi(k) < k, where phi is Euler's totient function.
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4
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OFFSET
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1,1
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COMMENTS
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By Mertens' theorem and the Prime Number Theorem log log a(n) ~ n / e^gamma. - Charles R Greathouse IV, Sep 07 2012
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LINKS
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Table of n, a(n) for n=1..9.
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PROG
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(PARI) a(n) = {k = 1; while (n*eulerphi(k) >= k, k++); k; } \\ Michel Marcus, Sep 25 2013
(PARI) a(n)=my(k=1); forprime(p=2, , if(n*eulerphi(k)<k, return(k), k*=p)) \\ Charles R Greathouse IV, Sep 25 2013
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CROSSREFS
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Subsequence of A002110. Cf. A000010, A054741, A073087, A091439 (n * phi(k) <= k).
Sequence in context: A077176 A101178 A294925 * A354411 A293756 A161620
Adjacent sequences: A091453 A091454 A091455 * A091457 A091458 A091459
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KEYWORD
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nonn
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AUTHOR
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Robert G. Wilson v, Jan 10 2004
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STATUS
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approved
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