# Find Nth term of the series 1, 1, 2, 6, 24…

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

1, 1, 2, 6, 24…

**Examples:**

Input:3Output:2 For N = 3 Nth term = (N-1)! = 2Input:5Output:24

Nth term of the series is given by below formula:

Nth term = ( N-1)!

Below is the required implementation:

## C++

`// CPP program to find N-th term of the series:` `// 1, 1, 2, 6, 24...` `#include <iostream>` `using` `namespace` `std;` `// calculate Nth term of series` `int` `nthTerm(` `int` `N)` `{` ` ` `if` `(N <= 1)` ` ` `return` `1;` ` ` `int` `i, fact = 1;` ` ` `for` `(i = 1; i < N; i++)` ` ` `fact = fact * i;` ` ` `return` `fact;` `}` `// Driver Function` `int` `main()` `{` ` ` `int` `N = 3;` ` ` `cout << nthTerm(N);` ` ` `return` `0;` `}` |

## Java

`// Java program to find the Nth term` `import` `java.io.*;` `// calculate Nth term of this series` `// 1, 1, 2, 6, 24...` `class` `Nth {` ` ` `public` `int` `nthTerm(` `int` `N)` ` ` `{` ` ` `// By using above formula` ` ` `if` `(N <= ` `1` `)` ` ` `return` `1` `;` ` ` `int` `i, fact = ` `1` `;` ` ` `for` `(i = ` `1` `; i < N; i++)` ` ` `fact = fact * i;` ` ` `return` `fact;` ` ` `}` `}` `// Main class for main method` `class` `GFG {` ` ` `public` `static` `void` `main(String[] args)` ` ` `{` ` ` `int` `N = ` `3` `;` ` ` `// create object of Class Nth` ` ` `Nth a = ` `new` `Nth();` ` ` `// call and print Nth term` ` ` `System.out.println(a.nthTerm(N));` ` ` `}` `}` |

## Python 3

`# Python 3 program to find` `# N-th term of the series:` `# 1, 1, 2, 6, 24...` `# Function to calculate` `# Nth term of series` `def` `nthTerm(n) :` ` ` `if` `n <` `=` `1` `:` ` ` `return` `1` ` ` `fact ` `=` `1` ` ` `for` `i ` `in` `range` `(` `1` `, N) :` ` ` `fact ` `=` `fact ` `*` `i` ` ` `return` `fact` `# Driver code` `if` `__name__ ` `=` `=` `"__main__"` `:` ` ` `N ` `=` `3` ` ` `# function calling` ` ` `print` `(nthTerm(N))` `# This code is contributed` `# by ANKITRAI1` |

## C#

`// C# program to find the` `// Nth term of the series` `// 1, 1, 2, 6, 24...` `using` `System;` `// calculate Nth term` `class` `GFG` `{` `public` `int` `nthTerm(` `int` `N)` `{` ` ` `// By using above formula` ` ` `if` `(N <= 1)` ` ` `return` `1;` ` ` `int` `i, fact = 1;` ` ` `for` `(i = 1; i < N; i++)` ` ` `fact = fact * i;` ` ` `return` `fact;` `}` `// Driver Code` `public` `static` `void` `Main()` `{` ` ` `int` `N = 3;` ` ` `// create object of Class GFG` ` ` `GFG a = ` `new` `GFG();` ` ` `// call and print Nth term` ` ` `Console.Write(a.nthTerm(N));` `}` `}` `// This code is contributed` `// by ChitraNayal` |

## PHP

`<?php` `// PHP program to find N-th` `// term of the series:` `// 1, 1, 2, 6, 24...` `// calculate Nth term of series` `function` `nthTerm(` `$N` `)` `{` ` ` `if` `(` `$N` `<= 1)` ` ` `return` `1;` ` ` `$fact` `= 1;` ` ` `for` `(` `$i` `= 1; ` `$i` `< ` `$N` `; ` `$i` `++)` ` ` `$fact` `= ` `$fact` `* ` `$i` `;` ` ` `return` `$fact` `;` `}` `// Driver Code` `$N` `= 3;` `echo` `nthTerm(` `$N` `);` `// This code is contributed` `// by ChitraNayal` `?>` |

## Javascript

`<script>` `// JavaScript program to find N-th term of the series:` `// 1, 1, 2, 6, 24...` `// calculate Nth term of series` `function` `nthTerm( N)` `{` ` ` `if` `(N <= 1)` ` ` `return` `1;` ` ` `let i, fact = 1;` ` ` `for` `(i = 1; i < N; i++)` ` ` `fact = fact * i;` ` ` `return` `fact;` `}` `// Driver Function` ` ` `let N = 3;` ` ` `document.write(nthTerm(N));` ` ` `// This code contributed by Rajput-Ji` `</script>` |

**Output:**

2

* Time Complexity: *O(N), where N represents the given integer.

*O(1), no extra space is required, so it is a constant.*

**Auxiliary Space:**