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A164347
The n-th term is the minimum number x such that x/Totient(x) >= n
1
2, 2, 6, 30, 210, 30030, 223092870, 13082761331670030, 3217644767340672907899084554130
OFFSET
1,1
COMMENTS
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. - R. J. Mathar, Aug 17 2009
EXAMPLE
2 => 2/ Totient(2) = 2 (so it is both the first and 2nd entry of the sequence) 210 => 210 / Totient(210) = 210/48 >= 4
PROG
(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 */
CROSSREFS
Each number n in this sequence is of the form: primorial(x). A164348, the related sequence, contains the x's.
Sequence in context: A067644 A184312 A097801 * A052584 A094303 A117394
KEYWORD
easy,nonn
AUTHOR
Fred Schneider, Aug 13 2009
STATUS
approved