Find Nth term of the series 1, 8, 54, 384…

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

1, 8, 54, 384...

**Examples:**

Input :3Output :54 For N = 3 Nth term = ( 3*3) * 3! = 54Input :2Output :8

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

Nth term = ( N*N ) * ( N! )

Below is the implementation of the above approach:

## C++

`// CPP program to find N-th term of the series:` `// 1, 8, 54, 384...` `#include <iostream>` `using` `namespace` `std;` `// calculate factorial of N` `int` `fact(` `int` `N)` `{` ` ` `int` `i, product = 1;` ` ` `for` `(i = 1; i <= N; i++)` ` ` `product = product * i;` ` ` `return` `product;` `}` `// calculate Nth term of series` `int` `nthTerm(` `int` `N)` `{` ` ` `return` `(N * N) * fact(N);` `}` `// Driver Function` `int` `main()` `{` ` ` `int` `N = 4;` ` ` `cout << nthTerm(N);` ` ` `return` `0;` `}` |

## Java

`// Java program to find N-th term of the series:` `// 1, 8, 54, 384...` `import` `java.io.*;` `// Main class for main method` `class` `GFG {` ` ` `public` `static` `int` `fact(` `int` `N)` ` ` `{` ` ` `int` `i, product = ` `1` `;` ` ` `// Calculate factorial of N` ` ` `for` `(i = ` `1` `; i <= N; i++)` ` ` `product = product * i;` ` ` `return` `product;` ` ` `}` ` ` `public` `static` `int` `nthTerm(` `int` `N)` ` ` `{` ` ` `// By using above formula` ` ` `return` `(N * N) * fact(N);` ` ` `}` ` ` `public` `static` `void` `main(String[] args)` ` ` `{` ` ` `int` `N = ` `4` `; ` `// 4th term is 384` ` ` `System.out.println(nthTerm(N));` ` ` `}` `}` |

## Python 3

`# Python 3 program to find` `# N-th term of the series:` `# 1, 8, 54, 384...` `# calculate factorial of N` `def` `fact(N):` ` ` ` ` `product ` `=` `1` ` ` `for` `i ` `in` `range` `(` `1` `, N ` `+` `1` `):` ` ` `product ` `=` `product ` `*` `i` ` ` `return` `product` `# calculate Nth term of series` `def` `nthTerm(N):` ` ` `return` `(N ` `*` `N) ` `*` `fact(N)` `# Driver Code` `if` `__name__ ` `=` `=` `"__main__"` `:` ` ` `N ` `=` `4` ` ` `print` `(nthTerm(N))` `# This code is contributed` `# by ChitraNayal` |

## C#

`// C# program to find N-th` `// term of the series:` `// 1, 8, 54, 384...` `using` `System;` `class` `GFG` `{` `public` `static` `int` `fact(` `int` `N)` `{` ` ` `int` `i, product = 1;` ` ` ` ` `// Calculate factorial of N` ` ` `for` `(i = 1; i <= N; i++)` ` ` `product = product * i;` ` ` `return` `product;` `}` `public` `static` `int` `nthTerm(` `int` `N)` `{` ` ` `// By using above formula` ` ` `return` `(N * N) * fact(N);` `}` `// Driver Code` `public` `static` `void` `Main(String[] args)` `{` ` ` `int` `N = 4; ` `// 4th term is 384` ` ` `Console.WriteLine(nthTerm(N));` `}` `}` `// This code is contributed` `// by Kirti_Mangal` |

## PHP

`<?php` `// PHP program to find N-th` `/// term of the series:` `// 1, 8, 54, 384...` `// calculate factorial of N` `function` `fact(` `$N` `)` `{` ` ` `$product` `= 1;` ` ` `for` `(` `$i` `= 1; ` `$i` `<= ` `$N` `; ` `$i` `++)` ` ` `$product` `= ` `$product` `* ` `$i` `;` ` ` `return` `$product` `;` `}` `// calculate Nth term of series` `function` `nthTerm(` `$N` `)` `{` ` ` `return` `(` `$N` `* ` `$N` `) * fact(` `$N` `);` `}` `// Driver Code` `$N` `= 4;` `echo` `nthTerm(` `$N` `);` `// This code is contributed` `// by ChitraNayal` `?>` |

## Javascript

`<script>` `// JavaScript program to find N-th term of the series:` `// 1, 8, 54, 384...` `// calculate factorial of N` `function` `fact( N)` `{` ` ` `let i, product = 1;` ` ` `for` `(i = 1; i <= N; i++)` ` ` `product = product * i;` ` ` `return` `product;` `}` `// calculate Nth term of series` `function` `nthTerm( N)` `{` ` ` `return` `(N * N) * fact(N);` `}` `// Driver Function` ` ` `let N = 4;` ` ` `document.write(nthTerm(N));` ` ` `// This code contributed by Rajput-Ji` `</script>` |

**Output:**

384

**Time Complexity:** O(N)

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