A015763 -id:A015763 - cp's OEIS frontend

A094468 Numbers k such that sum of 9th powers of divisors of k is divisible by the square of Euler-phi of k.

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

Offset: 1

Labos Elemer, May 19 2004

nonn

Amiram Eldar, Table of n, a(n) for n = 1..420

Cf. A015763, A000010, A091285, A013957.

Select[Range[2600000],Divisible[Total[Divisors[#]^9],(EulerPhi[#])^2]&]  (* Harvey P. Dale, Mar 04 2011 *)

for(n=1,10000000,if(Mod(sigma(n,9),eulerphi(n)^2)==0,print1(n,","))) \\ C. Ronaldo

A013957(k)/A000010(k)^2 is an integer.

More terms from C. Ronaldo (aga_new_ac(AT)hotmail.com), Jan 18 2005

A093038 Numbers k such that sum of 5th powers of divisors of k is divisible by the square of Euler-phi of k.

Original entry on oeis.org

1, 2, 3, 6, 322, 966, 473732, 1420296, 6655780894

Offset: 1

Labos Elemer, May 19 2004

No more terms through 10^9. - Ryan Propper, Jan 09 2007

Cf. A000010, A015763, A091285.

Do[ If[ Mod[ DivisorSigma[5, n], EulerPhi[n]^2] == 0, Print[n]], {n, 10^7}] (* Robert G. Wilson v, May 23 2004 *)

isok(k) = (sigma(k, 5) % eulerphi(k)^2) == 0; \\ Michel Marcus, Mar 07 2020

A001160(k)/A000010(k)^2 is an integer.

a(9) from Amiram Eldar, Mar 07 2020

A094469 Numbers k such that sum of 11th powers of divisors of k is divisible by the square of Euler-phi of k.

Original entry on oeis.org

1, 2, 3, 6, 1645, 3290, 4935, 9870, 3831674, 11495022, 346014339, 692028678

Offset: 1

Labos Elemer, May 19 2004

Cf. A000010, A013959, A015763, A091285.

Do[ If[ Mod[ DivisorSigma[11, n], EulerPhi[n]^2] == 0, Print[n]], {n, 10^7}] (* Robert G. Wilson v, May 23 2004 *)

isok(k) = (sigma(k, 11) % eulerphi(k)^2) == 0; \\ Michel Marcus, Mar 07 2020

A013959(k)/A000010(k)^2 is an integer.

a(9) from Robert G. Wilson v, May 23 2004
a(10) from Labos Elemer, May 26 2004
a(6) corrected and a(11)-a(12) added by Amiram Eldar, Mar 07 2020

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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.

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A093038 Numbers k such that sum of 5th powers of divisors of k is divisible by the square of Euler-phi of k.

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Mathematica

PARI

Formula

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A094469 Numbers k such that sum of 11th powers of divisors of k is divisible by the square of Euler-phi of k.

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Author

Keywords

Crossrefs

Programs

Mathematica

PARI

Formula

Extensions