Program to find Nth term of series 2, 12, 28, 50, 77, 112, 152, 198, …..

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

2, 12, 28, 50, 77, 112, 152, 198…..(N Terms)

Examples:

Input: N = 4
Output: 50
For N = 4
4th Term = ( 3 * 4 * 4 + 4 - 2) 
         = 50

Input: N = 10
Output: 307

Approach: The generalized Nth term of this series: 

Below is the required implementation: 

C++

// C++ program to find the N-th term of the series:
// 2, 12, 28, 50, 77, 112, 152, 198, .....
#include <iostream>
#include <math.h>
using namespace std;

// calculate Nth term of series
int nthTerm(int n)
{
    return 3 * pow(n, 2) + 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:
// 2, 12, 28, 50, 77, 112, 152, 198, .....
import java.util.*;

class solution
{

// calculate Nth term of series
static int nthTerm(int n)
{
return 3 *(int)Math.pow(n, 2) + n - 2;
}

//Driver program
public static void main(String arr[])
{

    int N = 4;
    System.out.println(nthTerm(N));
}

}
//This code is contributed by Surendra_Gangwar

Python3

# Python3 program to find the
# N-th term of the series:
# 2, 12, 28, 50, 77, 112, 152, 198, .....

# calculate Nth term of series
def nthTerm(n):

    return 3 * pow(n, 2) + 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:
// 2, 12, 28, 50, 77, 112, 152, 198, .....
using System;

class GFG
{

// calculate Nth term of series
static int nthTerm(int n)
{
    return 3 * (int)Math.Pow(n, 2) +
                             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:
// 2, 12, 28, 50, 77,
// 112, 152, 198, .....

// calculate Nth term of series
function nthTerm($n)
{
    return 3 * pow($n, 2) + $n - 2;
}

// Driver code
$N = 4;

echo nthTerm($N) ;

// This code is contributed
// by inder_verma
?>

Javascript

<script>
// JavaScript program to find the N-th term of the series:
// 2, 12, 28, 50, 77, 112, 152, 198, .....

// calculate Nth term of series
function nthTerm( n)
{
    return 3 * Math.pow(n, 2) + n - 2;
}

// Driver code
let N = 4;

   document.write( nthTerm(N) );

// This code contributed by gauravrajput1

</script>

Output:

50

Time Complexity: O(1)

Auxiliary Space: O(1) since using constant variables