# Find Nth term of the series 0, 2, 4, 8, 12, 18…

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

0, 2, 4, 8, 12, 18…

Examples:

```Input: 3
Output: 4
For N = 3
Nth term = ( 3 + ( 3 - 1 ) * 3 ) / 2
= 4
Input: 5
Output: 12
```

## Recommended: Please try your approach on {IDE} first, before moving on to the solution.

On observing carefully, the Nth term in the above series can be generalized as:

`Nth term = ( N + ( N - 1 ) * N ) / 2`

Below is the implementation of the above approach:

## C++

 `// CPP program to find N-th term of the series: ` `// 0, 2, 4, 8, 12, 18... ` `#include ` `using` `namespace` `std; ` ` `  `// Calculate Nth term of series ` `int` `nthTerm(``int` `N) ` `{ ` `    ``return` `(N + N * (N - 1)) / 2; ` `} ` ` `  `// Driver Function ` `int` `main() ` `{ ` `    ``int` `N = 5; ` ` `  `    ``cout << nthTerm(N); ` ` `  `    ``return` `0; ` `} `

## Java

 `// Java program to find N-th term of the series: ` `// 0, 2, 4, 8, 12, 18... ` `import` `java.io.*; ` ` `  `// Main class for main method ` `class` `GFG { ` `    ``public` `static` `int` `nthTerm(``int` `N) ` `    ``{ ` `        ``// By using above formula ` `        ``return` `(N + (N - ``1``) * N) / ``2``; ` `    ``}    ` `  `  `    ``// Driver code ` `    ``public` `static` `void` `main(String[] args) ` `    ``{ ` `        ``int` `N = ``5``; ``// 5th term is 12 ` `             `  `        ``System.out.println(nthTerm(N)); ` `    ``} ` `} `

## Python 3

 `# Python 3 program to find N-th term of the series:  ` `# 0, 2, 4, 8, 12, 18. ` ` `  `# Calculate Nth term of series ` `def` `nthTerm(N) : ` `     `  `    ``return` `(N ``+` `N ``*` `(N ``-` `1``)) ``/``/` `2` ` `  `# Driver Code ` `if` `__name__ ``=``=` `"__main__"` `: ` ` `  `    ``N ``=` `5` ` `  `    ``print``(nthTerm(N)) ` ` `  `# This code is contributed by ANKITRAI1 `

## C#

 `// C# program to find N-th term of the series: ` `// 0, 2, 4, 8, 12, 18... ` `using` `System; ` `class` `gfg ` `{    ` `    ``// Calculate Nth term of series ` `    ``public` `int` `nthTerm(``int` `N) ` `    ``{ ` `        ``int` `n = ((N + N * (N - 1)) / 2); ` `        ``return` `n; ` `    ``} ` ` `  `    ``//Driver program ` `    ``static` `void` `Main(``string``[] args) ` `    ``{ ` `        ``gfg p = ``new` `gfg(); ` `        ``int` `a = p.nthTerm(5); ` `        ``Console.WriteLine(a); ` `        ``Console.Read(); ` `    ``} ` `} ` `//This code is contributed by SoumikMondal `

## PHP

 ` `

Output:

```12
```

Time Complexity: O(1)

My Personal Notes arrow_drop_up

Strategy Path planning and Destination matters in success No need to worry about in between temporary failures

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.

Please Improve this article if you find anything incorrect by clicking on the "Improve Article" button below.