All of the mathematical puzzles on this webpage are very challenging.
We will post the names of anyone who solves them.
-
* indicates I have only a partial solution.
** indicates I do not have a solution.
** Rubin's Conjecture #1
      
Prove or disprove that every integer can be expressed as a sum of 3 distinct
powers,   xa + yb + zc  
where   x, y, z, a, b, c   are all integers, and
  1<a<b<c.
      
For a table showing how each of the integers from -100 to +100
can be expressed in this form CLICK HERE.
For a table showing how each of the integers from -8000 to +8000
can be expressed in this form CLICK HERE.
** Rubin's Conjecture #2
      
Prove or disprove that all but a finite number of integers can be expressed
as a sum of 3 powers,   xa + yb + zc
  where   x, y, z, a, b, c   are all positive integers, and
  1<a<b<c.