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Search: id:A164347
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| A164347 |
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The nth term is the minimum number x such that x/Totient(x) >= n |
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+0
2
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| 2, 2, 6, 30, 210, 30030, 223092870, 13082761331670030, 3217644767340672907899084554130
(list; graph; listen)
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OFFSET
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1,1
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COMMENT
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These numbers are all primorials. Primorials necessarily must be the minimum terms in this sequence (given the nature of Euler's Totient function).
Essentially the same as A091456. [From R. J. Mathar (mathar(AT)strw.leidenuniv.nl), Aug 17 2009]
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LINKS
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Euler's Totient Function
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EXAMPLE
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2 => 2/ Totient(2) = 2 (so it is both the 1st and 2nd entry of the sequence) 210 => 210 / Totient(210) = 210/48 >= 4
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PROGRAM
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(PARI) mm=3; n=2; m=1; forprime(x=3, 1000, n*=x; m*= (x-1); if (n\m >= mm, mm+=1; print(n))); /* Note: this will generate all terms of this sequence from the 3rd onward. The terms are easy to generate but grow very rapidly */
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CROSSREFS
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Each number n in this sequence is of the form: primorial(x). A164348, the related sequence, contains the x's.
Sequence in context: A058250 A067644 A097801 this_sequence A052584 A094303 A117394
Adjacent sequences: A164344 A164345 A164346 this_sequence A164348 A164349 A164350
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KEYWORD
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easy,nonn
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AUTHOR
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Fred Schneider (frederick.william.schneider(AT)gmail.com), Aug 13 2009
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