杭电OJ2050

                             

   由递推式可直接推出公式，如：

   f(n) = f(n-1) + n

          = ( f(n-2) + n-1 ) + n

          = ...

          = f(1) + 2 + 3 + ... + n = 2 + 2 + 3 + ... + n = 1 + 1 + 2 + 3 + ... + n = 1 + n(n+1)/2

import java.util.Scanner;

public class Main {
   public static void main(String[] args){
	   Scanner in = new Scanner(System.in);
	   int loop;
	   int temp;
	   long[] a = new long[10001];
	   a[1] = 2;
	   for(int i = 2; i < 10001; i++){
		   a[i] = a[i - 1] + 4 * (i - 1) + 1;
	   }
	   loop = in.nextInt();
	   for(int i = 0; i < loop; i++){
		   temp = in.nextInt();
		   System.out.println(a[temp]);
	   }
   }
}