OFFSET
1,1
MATHEMATICA
Select[Range[4600], Divisible[DivisorSigma[1, # + 9], EulerPhi[#] + 9] &] (* Amiram Eldar, Dec 10 2018 *)
CROSSREFS
KEYWORD
nonn
AUTHOR
EXTENSIONS
Incorrect a(1)=1 removed and title corrected by Sean A. Irvine, Dec 10 2018
STATUS
approved