OFFSET
1,2
COMMENTS
sigma_9(n) = A013957(n) is the sum of the 9th powers of the divisors of n.
LINKS
Amiram Eldar, Table of n, a(n) for n = 1..10000
MATHEMATICA
Select[Range[500], Divisible[DivisorSigma[9, #], EulerPhi[#]] &] (* Amiram Eldar, Nov 02 2019 *)
CROSSREFS
KEYWORD
nonn
AUTHOR
EXTENSIONS
Offset corrected by Amiram Eldar, Nov 02 2019
STATUS
approved