title: form a number using consecutive numbers
body: <p>I was puzzled with one of the question in Microsoft interview which is as given below:</p>
  
  <p>A function should accept a range( 3 - 21 ) and it should print all the consecutive numbers combinations to form each number as given below:</p>
  
  <pre>
  3  = 1+2
  5  = 2+3
  6  = 1+2+3
  7  = 3+4
  9  = 4+5
  10 = 1+2+3+4
  11 = 5+6
  12 = 3+4+5
  13 = 6+7
  14 = 2+3+4+5
  15 = 1+2+3+4+5
  17 = 8+9
  18 = 5+6+7
  19 = 9+10
  20 = 2+3+4+5+6
  21 = 10+11
  21 = 1+2+3+4+5+6</pre>
  
  <p>could you please help me in forming this sequence in C#?</p>
  
  <p>Thanks,
  Mahesh</p>