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# Find nth term of series 3, 11, 31, 69, . . . . .

Given an integer N, the task is to find the Nth term of the series

3, 11, 31, 69, . . . . . till Nth term.

Examples:

Input: N = 3
Output: 31

Input: N = 6
Output: 223

Approach:

From the given series, find the formula for Nth term

1st term = 1 ^ 3 + (1 + 1) = 3

2nd term = 2 ^ 3 + (2 + 1) = 11

3rd term = 3 ^ 3 + (3 + 1) = 31

4th term = 4 ^ 3 + (4 + 1) = 69

.

.

Nth term = n  ^ 3 + (n + 1)

The Nth term of the given series can be generalized as-

TN = n  ^ 3 + (n + 1)

Illustration:

Input: N = 5
Output: 131
Explanation:
TN = n  ^ 3 + (n + 1)
= 5 ^ 3 + (5 + 1)
= 131

Below is the implementation of the above approach-

## C++

 `// C++ program to find nth``// term of the series``#include ``using` `namespace` `std;` `// Function to return nth``// term of the series``int` `find_nth_Term(``int` `n)``{``    ``return` `n * n * n + (n + 1);``}` `// Driver code``int` `main()``{``    ``// Find given nth term``    ``int` `n = 5;` `    ``// Function call``    ``cout << find_nth_Term(n) << endl;``    ``return` `0;``}`

## Java

 `// Java code for the above approach``import` `java.io.*;` `class` `GFG {` `  ``// Function to return nth``  ``// term of the series``  ``static` `int` `find_nth_Term(``int` `n)``  ``{``    ``return` `n * n * n + (n + ``1``);``  ``}` `  ``// Driver code``  ``public` `static` `void` `main(String[] args)``  ``{` `    ``// Find given nth term``    ``int` `n = ``5``;` `    ``// Function call``    ``System.out.println(find_nth_Term(n));``  ``}``}` `// This code is contributed by Potta Lokesh`

## Python

 `# Python program to find nth``# term of the series` `# Function to return nth``# term of the series``def` `find_nth_Term(n):``    ` `    ``return` `n ``*` `n ``*` `n ``+` `(n ``+` `1``)` `# Driver code` `# Find given nth term``n ``=` `5` `# Function call``print``(find_nth_Term(n))` `# This code is contributed by Samim Hossain Mondal.`

## C#

 `// C# program to find nth``// term of the series``using` `System;``class` `GFG``{` `  ``// Function to return nth``  ``// term of the series``  ``static` `int` `find_nth_Term(``int` `n)``  ``{``    ``return` `n * n * n + (n + 1);``  ``}` `  ``// Driver code``  ``public` `static` `int` `Main()``  ``{` `    ``// Find given nth term``    ``int` `n = 5;` `    ``// Function call``    ``Console.WriteLine(find_nth_Term(n));``    ``return` `0;``  ``}``}` `// This code is contributed by Taranpreet`

## Javascript

 ``

Output

`131`

Time Complexity: O(1), since there is no loop or recursion.
Auxiliary Space: O(1), since no extra space has been taken.

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