title: i need to find the upper bound of this: or the tight bound:
body: <p>lets say i have an expression:</p>
  
  <pre><code>(n)+((n-1)*2)+((n-2)*3)+((n-3)*4)+...+(3*(n-2))+(2*(n-1))+(1*(n))
  </code></pre>
  
  <p>what is the tight bound of this? or the upper bound? is this n^3? is this n^4? the maximum amount of number i can get out of this? thanks</p>
  
  <p>EDIT: so: for i=1 then: the ans is 1.</p>
  
  <p>i=2: (1*2 + 2*1)
  1=3: (1*3 + 2*2 + 3*1)
  i=4: (1*4 + 2*3 + 3*2 + 4*1 ) </p>
  
  <p>and so on</p>