login
This site is supported by donations to The OEIS Foundation.

 

Logo


Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A046755 Numbers k such that d(k)^3 divides k. 5

%I

%S 1,625,6561,21952,32768,64000,98304,117649,163840,229376,360448,

%T 425984,557056,622592,753664,950272,1015808,1212416,1343488,1362944,

%U 1409024,1540096,1736704,1933312,1998848,2195456,2326528,2392064,2588672

%N Numbers k such that d(k)^3 divides k.

%C Proper subset of both A033950 and A046754. If two terms in the sequence are coprime then their product is also in the sequence.

%H Donovan Johnson, <a href="/A046755/b046755.txt">Table of n, a(n) for n = 1..1000</a>

%e If k = 21952, d(k) = sigma(0,k) = 28. Its 3rd power is 21952, which divides k.

%e a(103) = 14385152 = (2^15)*439 with 32 divisors and 14385152/(32^3) = 439; 2^15*prime is a typical form of terms in the sequence that have 32 divisors.

%t Select[ Range[ 1, 14500000 ], IntegerQ[ #/(DivisorSigma[ 0, # ])^3 ]& ]

%Y Cf. A033950, A046754, A046756.

%K nonn

%O 1,2

%A _Labos Elemer_

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recent
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy. .

Last modified March 18 13:47 EDT 2019. Contains 321289 sequences. (Running on oeis4.)