wu :: forums
wu :: forums - sum of distinct cubes

Welcome, Guest. Please Login or Register.
Nov 28th, 2023, 5:06pm

RIDDLES SITE WRITE MATH! Home Home Help Help Search Search Members Members Login Login Register Register
   wu :: forums
   riddles
   medium
(Moderators: towr, SMQ, Icarus, william wu, Grimbal, ThudnBlunder, Eigenray)
   sum of distinct cubes
« Previous topic | Next topic »
Pages: 1  Reply Reply Notify of replies Notify of replies Send Topic Send Topic Print Print
   Author  Topic: sum of distinct cubes  (Read 763 times)
Christine
Full Member
***





   


Posts: 159
sum of distinct cubes  
« on: Aug 14th, 2014, 9:42am »
Quote Quote Modify Modify

Cubes with a representation as a sum of distinct cubes :
 
Some end with a 1^3  : 9^3 = 8^3 + 6^3 + 1^3
 
others don't : 6^3 = 5^3 + 4^3 + 3^3
 
Is the set of those that don't finite or infinite?
 
How to prove it?
 
IP Logged
towr
wu::riddles Moderator
Uberpuzzler
*****



Some people are average, some are just mean.

   


Gender: male
Posts: 13730
Re: sum of distinct cubes  
« Reply #1 on: Aug 14th, 2014, 10:08am »
Quote Quote Modify Modify

multiply by n^3
if a^3 = b^3 + c^3 + d^3 then (an)^3 = (bn)^3 + (cn)^3 + (dn)^3
IP Logged

Wikipedia, Google, Mathworld, Integer sequence DB
Pages: 1  Reply Reply Notify of replies Notify of replies Send Topic Send Topic Print Print

« Previous topic | Next topic »

Powered by YaBB 1 Gold - SP 1.4!
Forum software copyright 2000-2004 Yet another Bulletin Board