OFFSET
1,1
MATHEMATICA
Select[Range[3000], Divisible[DivisorSigma[1, #], EulerPhi[11 + #]] &] (* David Nacin, Mar 01 2012 *)
PROG
(PARI) is(n)=!(sigma(n)%eulerphi(n+11)) \\ Charles R Greathouse IV, Sep 25 2012
CROSSREFS
KEYWORD
nonn
AUTHOR
STATUS
approved