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

 

Logo


Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A048698 Nonprime numbers n such that sum of aliquot divisors of n is a cube. 3
1, 10, 49, 56, 69, 76, 122, 133, 568, 578, 1001, 1018, 1243, 1324, 1431, 1611, 1685, 1819, 1994, 2296, 2323, 3344, 3403, 3627, 3641, 3763, 3981, 4336, 5482, 8186, 9077, 9641, 10113, 10688, 13471, 14188, 14509, 14727, 15940, 16697, 17141, 17619, 19241, 19637 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

The sum of the aliquot divisors of a prime is exactly 1. - Martin Renner, Oct 13 2011

LINKS

Donovan Johnson, Table of n, a(n) for n = 1..1000

EXAMPLE

a(4) = 56: the aliquot divisors 1,2,4,7,8,14,28 sum to 64, a cube.

MAPLE

a := []; for n from 1 to 1000 do if sigma(n) <> n+1 and type( simplify((sigma(n)-n)^(1/3)), `integer`) then a := [op(a), n]; fi; od: a;

PROG

(PARI) c=0; for(n=1, 13127239, if(isprime(n)==0, if(ispower(sigma(n)-n, 3), c++; write("b048698.txt", c " " n)))) /* Donovan Johnson, Mar 10 2013 */

CROSSREFS

Cf. A020477, A048699, A194948.

Sequence in context: A084857 A126734 A264266 * A045770 A217165 A154066

Adjacent sequences:  A048695 A048696 A048697 * A048699 A048700 A048701

KEYWORD

easy,nonn

AUTHOR

Enoch Haga

STATUS

approved

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

License Agreements, Terms of Use, Privacy Policy .

Last modified May 23 06:42 EDT 2017. Contains 286909 sequences.