OFFSET
1,1
LINKS
Amiram Eldar, Table of n, a(n) for n = 1..10000
MATHEMATICA
Select[Range[4100], ! PrimeQ[#] && Numerator[#/EulerPhi[#] - DivisorSigma[1, #]/#] == 1 &] (* Jayanta Basu, Jul 01 2013 *)
PROG
(PARI) isok(k) = if (!isprime(k), numerator(k/eulerphi(k) - sigma(k)/k) == 1); \\ Michel Marcus, May 10 2022
CROSSREFS
KEYWORD
easy,nonn
AUTHOR
Benoit Cloitre, Aug 27 2002
STATUS
approved