login
A015767
Numbers k such that phi(k) | sigma_9(k).
10
1, 2, 3, 6, 12, 14, 15, 30, 35, 38, 42, 54, 56, 70, 78, 87, 95, 105, 114, 126, 135, 140, 147, 168, 174, 182, 190, 209, 210, 215, 216, 222, 248, 258, 264, 266, 270, 285, 294, 297, 315, 342, 357, 378, 418, 420, 430, 447, 455, 456, 494, 518, 540, 546
OFFSET
1,2
COMMENTS
sigma_9(n) = A013957(n) is the sum of the 9th powers of the divisors of n.
LINKS
MATHEMATICA
Select[Range[500], Divisible[DivisorSigma[9, #], EulerPhi[#]] &] (* Amiram Eldar, Nov 02 2019 *)
KEYWORD
nonn
EXTENSIONS
Offset corrected by Amiram Eldar, Nov 02 2019
STATUS
approved