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Program to find Nth term of series 1, 6, 17, 34, 56, 86, 121, 162, …….
  • Last Updated : 10 Mar, 2021

Given a number N. The task is to write a program to find the Nth term of the below series:
 

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

Examples: 
 

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

Input: N = 10
Output: 261

 

Approach: The generalized Nth term of this series: 
 



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

Below is the required implementation: 
 

C++




// C++ program to find the N-th term of the series:
// 1, 6, 17, 34, 56, 86, 121, 162, .....
#include <iostream>
#include <math.h>
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

PHP




<?php
// PHP 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($n)
{
    return 3 * pow($n, 2) -
           4 * $n + 2;
}
 
// Driver code
$N = 4;
 
echo nthTerm($N)."\n";
 
// This code is contributed
// by ChitraNayal
?>

Javascript




<script>
// 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
 
</script>
Output: 
34

 

Time Complexity: O(1)
 

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