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A091495 Odd, squarefree n such that n/phi(n) > 2, where phi is Euler's totient function. 3
105, 165, 195, 1155, 1365, 1785, 1995, 2145, 2415, 2805, 3003, 3045, 3135, 3255, 3315, 3705, 3795, 3885, 3927, 4305, 4389, 4485, 4515, 4641, 4785, 4845, 4935, 5115, 5187, 5313, 5565, 5655, 5865, 6045, 6105, 6195, 6405, 6555, 6765, 7035, 7095, 7215 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Apparently the squarefree members of the sequence A036798. Note that 105, 165 and 195 are the only terms having 3 prime factors. Also note that all the numbers listed above have 3 as a factor. The smallest number of this form not divisible by 3 is 37182145 = 5*7*11*13*17*19*23.

LINKS

T. D. Noe, Table of n, a(n) for n=1..1000

MATHEMATICA

lst={}; Do[f=FactorInteger[n]; s=Times@@Last/@f; If[s==1&&Times@@(1-1/(First/@f))<1/2, AppendTo[lst, n]], {n, 3, 10000, 2}]; lst

Select[Range[1, 7301, 2], SquareFreeQ[#]&&#/EulerPhi[#]>2&] (* Harvey P. Dale, Jul 10 2017 *)

CROSSREFS

Cf. A036798.

Cf. A118700

Sequence in context: A076762 A036798 A119434 * A256673 A046405 A128278

Adjacent sequences:  A091492 A091493 A091494 * A091496 A091497 A091498

KEYWORD

nonn

AUTHOR

T. D. Noe, Jan 15 2004

STATUS

approved

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Last modified May 26 19:44 EDT 2019. Contains 323597 sequences. (Running on oeis4.)