Calculate the formula

Problem Description
You just need to calculate the sum of the formula: 1^2+3^2+5^2+……+ n ^2.

Input
In each case, there is an odd positive integer n.

Output
Print the sum. Make sure the sum will not exceed 2^31-1

Sample Input
3

Sample Output
10

http://blog.csdn.net/ac_gibson/article/details/40976603

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