Question 941138
<pre>
 2,       M,      N ,     250  
 &#8741;        &#8741;       &#8741;        &#8741;  
 2,      2r,     2r²,     2r³
 &#8741;        &#8741;       &#8741;        &#8741; 
2=2,    M=2r,   N=2r²,  2r³=250
          &#8741;       &#8741;      r³=125      
          &#8741;       &#8741;       r=5
          &#8741;       &#8741;        
       M=2r,    N=2r²
       M=2(5)   N=2(5)²
       M=10     N=2(25)
                N=50 

Sequence: 2,M,N,250 = 2,10,50,250 
 
Edwin</pre>