程序找到系列1、6、17、34、56、86、121、162，……的N个项。

给定数字N。任务是编写一个程序来查找以下系列的第N个术语：

1, 6, 17, 34, 56, 86, 121, 162, …..(N Terms)

例子：

Input: N = 4
Output: 34
For N = 4
4th Term = ( 3 * 4 * 4 - 4 * 4 + 2) 
         = 34

Input: N = 10
Output: 261

方法：本系列的广义第N个术语：

$nth\: Term\: of\: the\: series\: = 3*n^2-4*n+2$

以下是所需的实现：

C++

// C++ program to find the N-th term of the series:
// 1, 6, 17, 34, 56, 86, 121, 162, .....
#include 
#include 
using namespace std;
 
// calculate Nth term of series
int nthTerm(int n)
{
    return 3 * pow(n, 2) - 4 * n + 2;
}
 
// Driver code
int main()
{
    int N = 4;
 
    cout << nthTerm(N) << endl;
 
    return 0;
}

Java

// Java program to find the N-th term of the series:
// 1, 6, 17, 34, 56, 86, 121, 162, .....
 
public class GFG {
     
    // calculate Nth term of series
    static int nthTerm(int n)
    {
        return 3 * (int) Math.pow(n, 2) - 4 * n + 2;
    }
       
    // Driver code
    public static void main(String args[])
    {
        int N = 4;
           
       System.out.println(nthTerm(N));
     
    }
    // This Code is contributed by ANKITRAI1
}

Python3

# Python program to find the
# N-th term of the series:
# 1, 6, 17, 34, 56, 86, 121, 162, .....
 
# calculate Nth term of series
def nthTerm(n):
 
    return 3 * pow(n, 2) - 4 * n + 2
 
# Driver code
N = 4
print(nthTerm(N))
 
# This code is contributed by
# Sanjit_Prasad

C#

// C# program to find the
// N-th term of the series:
// 1, 6, 17, 34, 56, 86, 121, 162, .....
using System;
class GFG
{
     
// calculate Nth term of series
static int nthTerm(int n)
{
    return 3 * (int) Math.Pow(n, 2) -
                         4 * n + 2;
}
     
// Driver code
public static void Main()
{
    int N = 4;
         
    Console.Write(nthTerm(N));
}
}
 
// This code is contributed
// by ChitraNayal

Javascript

// JavaScript program to find the N-th term of the series:
// 1, 6, 17, 34, 56, 86, 121, 162, .....
 
// calculate Nth term of series
function nthTerm(n)
{
    return 3 * Math.pow(n, 2) - 4 * n + 2;
}
 
// Driver code
let N = 4;
 
     document.write( nthTerm(N) );
 
// This code contributed by gauravrajput1
 

输出：

34

时间复杂度： O(1)