OFFSET
1,1
LINKS
Vincenzo Librandi, Table of n, a(n) for n = 1..1300
MATHEMATICA
Select[Range[400], Divisible[DivisorSigma[1, #], EulerPhi[#]+4]&] (* Harvey P. Dale, Aug 05 2014 *)
PROG
(PARI) is(n)=!(sigma(n)%eulerphi(n+4)) \\ Charles R Greathouse IV, Sep 25 2012
CROSSREFS
KEYWORD
nonn
AUTHOR
STATUS
approved