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Product-Difference Crossed Power Poser (Posted on 2023-04-15) Difficulty: 4 of 5
Determine all possible triplet(s) of positive integers such that each of p*q-r, q*r-p, and r*p-q is a power of 2.
*** Adapted from a problem appearing in IMO 2015.

See The Solution Submitted by K Sengupta    
Rating: 5.0000 (1 votes)

Comments: ( Back to comment list | You must be logged in to post comments.)
Some Thoughts No Subject | Comment 1 of 2
clearvars,clc
for t=1:1000
  for p=1:t/3
    for q=p+1:(t-p)/2
      r=t-p-q;
      if p*q-r>0 && q*r-p>0 && p*r-q>0
        a=p*q-r; b=q*r-p; c=p*r-q;
        la=log(a)/log(2);lb=log(b)/log(2);lc=log(c)/log(2);
        if 2^round(la)==a  &&  2^round(lb)==b  &&  2^round(lc)==c  
        disp([p q r a b c] )
        end
      end
    end
  end
end

finds

     p     q     r     the formala values
     3     5     7     8    32    16
     2     6    11     1    64    16

no guaarantee of completeness. Of course the values of p, q and r can be rearranged.

  Posted by Charlie on 2023-04-15 10:58:47
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