OFFSET
1,2
LINKS
Amiram Eldar, Table of n, a(n) for n = 1..10000
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
KEYWORD
easy,nonn
AUTHOR
Benoit Cloitre, Apr 09 2002
STATUS
approved