OFFSET
1,2
COMMENTS
This is an infinite sequence; for example, 2^(m-1)*5^m is in the sequence for all m >= 2. See Bellaouar et al. 2023. - Allen Stenger, Feb 16 2024
LINKS
G. C. Greubel, Table of n, a(n) for n = 1..8407 (for values up to 500000)
Djamel Bellaouar, Abdelmadjid Boudaoud and Rafael Jakimczuk, Notes on the equation d(n) = d(phi(n)) and related inequalities, Math. Slovaca 73 (2023), no. 3, 613-632.
MATHEMATICA
Select[Range[600], DivisorSigma[0, #]==DivisorSigma[0, EulerPhi[#]]&] (* Harvey P. Dale, Sep 04 2015 *)
PROG
(PARI) for(n=1, 900, if(numdiv(n)==numdiv(eulerphi(n)), print1(n, ", ")))
CROSSREFS
KEYWORD
easy,nonn
AUTHOR
Benoit Cloitre, May 12 2002
STATUS
approved