OFFSET
1,1
MATHEMATICA
Select[Range[1, 10000], Divisible[DivisorSigma[1, #], EulerPhi[12 + #]] && !Mod[#, 3] == 0 &] (* David Nacin, Mar 04 2012 *)
PROG
(PARI) is(n)=n%3 && sigma(n)%eulerphi(n+12)==0 \\ Charles R Greathouse IV, Sep 25 2012
CROSSREFS
KEYWORD
nonn
AUTHOR
STATUS
approved