OFFSET
1,2
LINKS
Amiram Eldar, Table of n, a(n) for n = 1..10000
Jean-Marie De Koninck and Imre Kátai, On the coprimality of some arithmetic functions, Publications de l'Institut Mathématique, 2010 87(101):121-128.
MATHEMATICA
Select[Range[14000], CoprimeQ[EulerPhi[#], (d = DivisorSigma[0, #])] && CoprimeQ[DivisorSigma[1, #], d] &] (* Amiram Eldar, Aug 08 2020 *)
PROG
(PARI) isok(n) = (gcd(eulerphi(n), numdiv(n))==1) && (gcd(sigma(n), numdiv(n)) == 1);
CROSSREFS
KEYWORD
nonn
AUTHOR
Michel Marcus, Jan 12 2018
STATUS
approved