OFFSET
1,1
LINKS
Robert Israel, Table of n, a(n) for n = 1..10000
MAPLE
filter:= proc(n) uses numtheory;
sigma(n+3) mod (3+phi(n)) = 0
end proc:
select(filter, [$1..2000]); # Robert Israel, Jan 24 2022
MATHEMATICA
Select[Range[1100], Divisible[DivisorSigma[1, #+3], EulerPhi[#]+3]&] (* Harvey P. Dale, Sep 04 2013 *)
PROG
(PARI) is(n)=!(sigma(n+3)%(eulerphi(n)+3)) \\ Charles R Greathouse IV, Sep 25 2012
CROSSREFS
KEYWORD
nonn
AUTHOR
EXTENSIONS
Corrected by Charles R Greathouse IV, Sep 25 2012
STATUS
approved