OFFSET
1,1
LINKS
Vincenzo Librandi, Table of n, a(n) for n = 1..1000
MAPLE
select(t -> (numtheory:-sigma(t)/numtheory:-phi(t+3))::integer, [$1..1000]); # Robert Israel, Dec 13 2018
MATHEMATICA
Select[Range[1000], Divisible[DivisorSigma[1, #], EulerPhi[3 + #]] &] (* David Nacin, Mar 01 2012 *)
PROG
(PARI) is(n)=sigma(n)%(eulerphi(n+3))==0 \\ Charles R Greathouse IV, Sep 25 2012
CROSSREFS
KEYWORD
nonn
AUTHOR
STATUS
approved