hdu1249

纯规律题：找到n=3时，分割数为20，从而可发现2，8, 20之间差的关系正好是6的倍数。

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      #include
    
      "
    
      iostream
    
      "
    
      

    
      using
    
       
    
      namespace
    
       std;

    
      int
    
       a[
    
      10000
    
      ];

    
      int
    
       main()
{
 
    
      int
    
       t;
 
    
      int
    
       n;
 cin
    
      >>
    
      t;
 
    
      while
    
      (t
    
      --
    
      )
 {
 cin
    
      >>
    
      n;
 a[
    
      1
    
      ]
    
      =
    
      2
    
      ;
 
    
      for
    
      (
    
      int
    
       i
    
      =
    
      2
    
      ;i
    
      <=
    
      n;i
    
      ++
    
      )
 a[i]
    
      =
    
      a[i
    
      -
    
      1
    
      ]
    
      +
    
      6
    
      *
    
      (i
    
      -
    
      1
    
      );
 cout
    
      <<
    
      a[n]
    
      <<
    
      endl;
 }
 
    
      return
    
       
    
      0
    
      ;
}