P18993 [GeeksforGeeks] Difference series4345
普及-
题目描述

Given a series of numbers 3,10,21,36 …., and series starting from N = 1, find the pattern and output the N'th value of the above series.
Example 1:
Input:
N = 1
Output:
3
Explanation:
3 is the first term of the series.
Example 2:
Input:
N = 2
Output:
10
Explanation:
10 is the second term of the series.
Your Task:
You don't need to read input or print anything. Your task is to complete the function differenceSeries() which takes an integer N as input parameter and returns the N'th term of the series.
Expected Time Complexity: O(1)
Expected Auxiliary Space: O(1)
Constraints:
1 ≤ n ≤ 100

输入格式

见题面

输出格式

见题面

样例输入
N = 1
样例输出
3