title: TypeError: 'int' object is not subscriptable "str(n1[::-1])"
body: <p>I keep getting a error.</p>
  
  <p>line 8, in main
      n3 = str(n1) + str(n) + str(n1[::-1]) + str(n2)</p>
  
  <p>TypeError: 'int' object is not subscriptable</p>
  
  <pre><code>def main():
      n = eval(input("enter the number"))
  
      n1 = 1
      n2 = 21 
  
      for i in range(n-2):
  
          n3 = str(n1) + str(i+3) + str(n1[::-1]) + str(n2)
          print("\n",n3)
  
          n1 = n2
          n2 = n3
  main()
  </code></pre>
  
  <p>I am trying to store string(n1) + string(i+3) + string(reversed list of numbers) + string(n2) into a variable n3.</p>
  
  <p>I claimed the values as Strings and I don't understand why error says 'integer' object...</p>