Problem1301--C++二级辅导-等差数列

1301: C++二级辅导-等差数列

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Time Limit : 1.000 sec  Memory Limit : 128 MB

SubmitSolved: 3Submit Num: 5Statistics

Description



sum=2+5+8+11+14+…，输入正整数n，求sum的前n项和。


Sample Input Copy 

2

Sample Output Copy 

7

Source/Category

 
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