# Find the Nth term of the series 5, 13, 37, 109, 325, . . .

• Last Updated : 28 Jan, 2022

Given a positive integer N. The task is to find Nth term of the series 5, 13, 37, 109, 325, …..

Examples:

Input: N = 5
Output: 325
Explanation:  From the sequence it can be seen that the 5th term is 325

Input: N = 1
Output: 5
Explanation: The 1st term of the given sequence is 5

Approach: The sequence formed by using the following pattern. For any value N

TN = 4 * 3N – 1 + N

Below is the implementation of the above approach:

## C++

 `// C++ program to implement``// the above approach``#include ``using` `namespace` `std;` `// Function to return Nth term``// of the series``int` `calcNum(``int` `N)``{``  ``return` `4 * ``pow``(3, N - 1) + 1;``}` `// Driver Code``int` `main()``{``    ``int` `N = 5;` `    ``cout << calcNum(N);``    ``return` `0;``}`

## Java

 `// Java program to implement``// the above approach``import` `java.util.*;``public` `class` `GFG``{` `  ``// Function to return Nth term``  ``// of the series``  ``static` `int` `calcNum(``int` `N)``  ``{``    ``return` `4` `* (``int``)Math.pow(``3``, N - ``1``) + ``1``;``  ``}` `  ``// Driver Code``  ``public` `static` `void` `main(String args[])``  ``{``    ``int` `N = ``5``;``    ``System.out.println(calcNum(N));``  ``}``}` `// This code is contributed by Samim Hossain Mondal.`

## Python3

 `# Python 3 program for the above approach` `# Function to return Nth term``# of the series``def` `calcNum(N):``    ` `    ``return` `4` `*` `pow``(``3``, N ``-` `1``) ``+` `1` `# Driver Code``if` `__name__ ``=``=` `"__main__"``:` `    ``N``=``5` `    ``print``(calcNum(N))` `# This code is contributed by Abhishek Thakur.`

## C#

 `// C# program to implement``// the above approach``using` `System;` `public` `class` `GFG{` `  ``// Function to return Nth term``  ``// of the series``  ``static` `int` `calcNum(``int` `N)``  ``{``    ``return` `4 * (``int``)Math.Pow(3, N - 1) + 1;``  ``}` `  ``// Driver Code``  ``static` `public` `void` `Main ()``  ``{``    ``int` `N = 5;``    ``Console.Write(calcNum(N));``  ``}``}`  `// This code is contributed by SHubham Singh`

## Javascript

 ``

Output
`325`

Time Complexity: O(1)
Auxiliary Space: O(1)

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