OFFSET
1,2
COMMENTS
sigma_5(n) is the sum of the 5th powers of the divisors of n.
LINKS
David A. Corneth, Table of n, a(n) for n = 1..10000
EXAMPLE
sigma_5(12) = 1^5 + 2^5 + 3^5 + 4^5 + 6^5 + 12^5 = 257908. phi(12) = 4. sigma_5(12) = 257908 is divisible by phi(12) = 4 so 12 is in the sequence. - David A. Corneth, Aug 24 2019
MATHEMATICA
Select[Range[910], Divisible[DivisorSigma[5, #], EulerPhi[#]] &] (* Jon Maiga, Aug 24 2019 *)
PROG
(PARI) isok(n) = !(sigma(n, 5) % eulerphi(n)); \\ Michel Marcus, Aug 24 2019
(Magma) [k:k in [1..1000]| DivisorSigma(5, k) mod EulerPhi(k) eq 0]; // Marius A. Burtea, Aug 24 2019
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
STATUS
approved