# Find n-th term in the series 7, 15, 32, …

Given a series 7, 15, 32, …… Find the nth term of this series.

Examples :

```Input : 5
Output : 138

Input : 7
Output : 568
```

## Recommended: Please solve it on “PRACTICE” first, before moving on to the solution.

Approach : By seeing the pattern of the series we can easily identify that it is a mixed series.
S = 7, 15, 32…..
Each element in the series is multiplied by 2 and then incremented one more than the previous.
S = 7, 15 (2 * 7 + 1), 32 (2 * 15 + 2)…….

By using iteration we can easily find nth term of the series.

Below is the implementation of the above approach :

## C++

 `// CPP program to find nth term ` `#include ` `using` `namespace` `std; ` ` `  `// utility function ` `int` `findTerm(``int` `n) ` `{ ` `    ``if` `(n == 1) ` `        ``return` `n; ` ` `  `    ``else` `{ ` ` `  `        ``// since first element of the ` `        ``// series is 7, we initailise ` `        ``// a variable with 7 ` `        ``int` `term = 7; ` ` `  `        ``// Using iteration to find nth  ` `        ``// term ` `        ``for` `(``int` `i = 2; i <= n; i++)  ` `            ``term = term * 2 + (i - 1);         ` ` `  `        ``return` `term; ` `    ``} ` `} ` ` `  `// driver function ` `int` `main() ` `{ ` `    ``int` `n = 5; ` `    ``cout << findTerm(n); ` `    ``return` `0; ` `} `

## Java

 `// Java program to find nth term ` `import` `java.lang.*; ` ` `  `class` `GFG { ` `     `  `// utility function ` `static` `int` `findTerm(``int` `n) ` `{ ` `    ``if` `(n == ``1``) ` `    ``return` `n; ` ` `  `    ``else` `{ ` ` `  `    ``// since first element of the ` `    ``// series is 7, we initailise ` `    ``// a variable with 7 ` `    ``int` `term = ``7``; ` ` `  `    ``// Using iteration to find nth ` `    ``// term ` `    ``for` `(``int` `i = ``2``; i <= n; i++) ` `        ``term = term * ``2` `+ (i - ``1``); ` ` `  `    ``return` `term; ` `    ``} ` `} ` ` `  `// Driver code ` `public` `static` `void` `main(String[] args)  ` `{ ` `    ``int` `n = ``5``; ` `    ``System.out.print(findTerm(n)); ` `} ` `} ` ` `  `// This code is contributed by Anant Agarwal. `

## Python3

 `# Python3 program to find nth term ` ` `  `# utility function ` `def` `findTerm(n) : ` ` `  `    ``if` `n ``=``=` `1` `: ` `        ``return` `n ` `    ``else` `: ` `         `  `        ``# since first element of the ` `        ``# series is 7, we initailise ` `        ``# a variable with 7 ` `        ``term ``=` `7` ` `  `        ``# Using iteration to find nth  ` `        ``# term ` `        ``for` `i ``in` `range``(``2``, n ``+` `1``) : ` `            ``term ``=` `term ``*` `2` `+` `(i ``-` `1``);      ` ` `  `    ``return` `term; ` ` `  `# driver function ` `print` `(findTerm(``5``)) ` ` `  `# This code is contributed by Saloni Gupta `

## C#

 `// C# program to find nth term ` `using` `System; ` ` `  `class` `GFG { ` ` `  `    ``// utility function ` `    ``static` `int` `findTerm(``int` `n) ` `    ``{ ` `        ``if` `(n == 1) ` `            ``return` `n; ` ` `  `        ``else` `{ ` ` `  `            ``// since first element of the ` `            ``// series is 7, we initailise ` `            ``// a variable with 7 ` `            ``int` `term = 7; ` ` `  `            ``// Using iteration to find nth ` `            ``// term ` `            ``for` `(``int` `i = 2; i <= n; i++) ` `                ``term = term * 2 + (i - 1); ` ` `  `            ``return` `term; ` `        ``} ` `    ``} ` ` `  `    ``// Driver code ` `    ``public` `static` `void` `Main() ` `    ``{ ` `        ``int` `n = 5; ` `        ``Console.WriteLine(findTerm(n)); ` `    ``} ` `} ` ` `  `// This code is contributed by vt_m. `

## PHP

 ` `

Output :

```138
```

This article is contributed by Saloni Gupta . If you like GeeksforGeeks and would like to contribute, you can also write an article using contribute.geeksforgeeks.org or mail your article to contribute@geeksforgeeks.org. See your article appearing on the GeeksforGeeks main page and help other Geeks.