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 A069167 Numbers n such that n*sum( d divides n,1/phi(d)) is an integer. 1
 1, 2, 4, 6, 8, 9, 10, 12, 16, 18, 24, 32, 36, 42, 44, 48, 50, 54, 64, 72, 81, 90, 96, 100, 108, 114, 126, 128, 144, 150, 162, 184, 192, 198, 200, 216, 234, 250, 252, 256, 288, 294, 324, 378, 384, 396, 400, 432, 441, 450, 484, 486, 504, 512, 550, 558, 576, 588 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,2 LINKS MATHEMATICA Select[Range[600], IntegerQ[#(Total[1/(EulerPhi[Divisors[#]])])]&](* Harvey P. Dale, Dec 17 2018 *) PROG (PARI) is(n)=denominator(sumdiv(n, d, 1/eulerphi(d))*n)==1 \\ Charles R Greathouse IV, Oct 27 2015 CROSSREFS Sequence in context: A118672 A100417 A070089 * A217352 A036627 A191982 Adjacent sequences:  A069164 A069165 A069166 * A069168 A069169 A069170 KEYWORD easy,nonn AUTHOR Benoit Cloitre, Apr 09 2002 STATUS approved

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Last modified October 23 03:21 EDT 2019. Contains 328335 sequences. (Running on oeis4.)