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A094468 Numbers k such that sum of 9th powers of divisors of k is divisible by the square of Euler-phi of k. 2
1, 2, 3, 6, 14, 42, 3810, 26670, 34162, 41256, 48546, 87096, 102486, 131934, 210482, 288792, 315723, 318990, 430122, 529848, 609672, 631446, 979830, 1023366, 1203960, 1473374, 1683126, 1920699, 2210061, 2241934, 2506086, 2549610 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,2
LINKS
FORMULA
A013957(k)/A000010(k)^2 is integer.
MATHEMATICA
Select[Range[2600000], Divisible[Total[Divisors[#]^9], (EulerPhi[#])^2]&] (* Harvey P. Dale, Mar 04 2011 *)
PROG
(PARI) for(n=1, 10000000, if(Mod(sigma(n, 9), eulerphi(n)^2)==0, print1(n, ", "))) \\ C. Ronaldo
CROSSREFS
Sequence in context: A188775 A015892 A056569 * A091285 A109459 A118986
KEYWORD
nonn
AUTHOR
Labos Elemer, May 19 2004
EXTENSIONS
More terms from C. Ronaldo (aga_new_ac(AT)hotmail.com), Jan 18 2005
STATUS
approved

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Last modified June 12 23:56 EDT 2024. Contains 373362 sequences. (Running on oeis4.)