# Find the Nth term in series 12, 35, 81, 173, 357, …

Last Updated : 28 Jul, 2022

Given a number N, the task is to find the Nth term in series 12, 35, 81, 173, 357, …
Example:

```Input: N = 2
Output: 35
2nd term = (12*2) + 11
= 35

Input: N = 5
Output: 357
5th term = (12*(2^4))+11*((2^4)-1)
= 357```

Approach:

• Each and every number is obtained by multiplying the previous number by 2 and the addition of 11 to it.
• Since starting number is 12.

```1st term = 12
2nd term = (12 * 2) / 11 = 35
3rd term = (35 * 2) / 11 = 81
4th term = (81 * 2) / 11 = 173
And, so on....```
•
• In general, Nth number is obtained by formula:

•

Below is the implementation of the above approach:

## C++

 `// C++ program to find the Nth term` `// in series 12, 35, 81, 173, 357, ...`   `#include ` `using` `namespace` `std;`   `// Function to find Nth term` `int` `nthTerm(``int` `N)` `{` `    ``int` `nth = 0, first_term = 12;`   `    ``// Nth term` `    ``nth = (first_term * (``pow``(2, N - 1)))` `          ``+ 11 * ((``pow``(2, N - 1)) - 1);`   `    ``return` `nth;` `}`   `// Driver Method` `int` `main()` `{` `    ``int` `N = 5;` `    ``cout << nthTerm(N) << endl;`   `    ``return` `0;` `}`

## Java

 `// Java program to find the Nth term` `// in series 12, 35, 81, 173, 357, ...` `class` `GFG` `{`   `// Function to find Nth term` `static` `int` `nthTerm(``int` `N)` `{` `    ``int` `nth = ``0``, first_term = ``12``;`   `    ``// Nth term` `    ``nth = (``int``) ((first_term * (Math.pow(``2``, N - ``1``)))` `        ``+ ``11` `* ((Math.pow(``2``, N - ``1``)) - ``1``));`   `    ``return` `nth;` `}`   `// Driver code` `public` `static` `void` `main(String[] args)` `{` `    ``int` `N = ``5``;` `    ``System.out.print(nthTerm(N) +``"\n"``);` `}` `}`   `// This code is contributed by Rajput-Ji`

## Python3

 `# Python3 program to find the Nth term ` `# in series 12, 35, 81, 173, 357, ... `   `# Function to find Nth term ` `def` `nthTerm(N) :`   `    ``nth ``=` `0``; first_term ``=` `12``; `   `    ``# Nth term ` `    ``nth ``=` `(first_term ``*` `(``pow``(``2``, N ``-` `1``))) ``+` `\` `            ``11` `*` `((``pow``(``2``, N ``-` `1``)) ``-` `1``); `   `    ``return` `nth; `   `# Driver Method ` `if` `__name__ ``=``=` `"__main__"` `: `   `    ``N ``=` `5``; ` `    ``print``(nthTerm(N)) ; `   `# This code is contributed by AnkitRai01`

## C#

 `// C# program to find the Nth term` `// in series 12, 35, 81, 173, 357, ...` `using` `System;`   `class` `GFG` `{`   `// Function to find Nth term` `static` `int` `nthTerm(``int` `N)` `{` `    ``int` `nth = 0, first_term = 12;`   `    ``// Nth term` `    ``nth = (``int``) ((first_term * (Math.Pow(2, N - 1)))` `        ``+ 11 * ((Math.Pow(2, N - 1)) - 1));`   `    ``return` `nth;` `}`   `// Driver code` `public` `static` `void` `Main(String[] args)` `{` `    ``int` `N = 5;` `    ``Console.Write(nthTerm(N) +``"\n"``);` `}` `}`   `// This code is contributed by PrinciRaj1992`

## Javascript

 ``

Output:

`357`

Time complexity: O(log N) for given input N because using inbuilt pow function

Auxiliary Space: O(1)