OFFSET
1,1
COMMENTS
LINKS
Donovan Johnson, Table of n, a(n) for n = 1..1000
MATHEMATICA
Select[Range[122*10^5], DivisorSigma[1, #]/EulerPhi[#]==25/9&] (* Harvey P. Dale, Jun 20 2021 *)
PROG
(PARI) for( i=1, 1e7, sigma(i)/eulerphi(i)==25/9 && print1(i", "))
CROSSREFS
KEYWORD
nonn
AUTHOR
Farideh Firoozbakht and M. F. Hasler, Sep 23 2009
STATUS
approved