Given a number **N**, the task is to find **N ^{th}** 120-gon number.

A 120-gon number is a class of figurate numbers. It has 120 – sided polygon called 120-gon. The N-th 120-gon number count’s the 120 number of dots and all other dots are surrounding with a common sharing corner and make a pattern. The first few 120-gon numbers are

1, 120, 357, 712, 1185, 1776, …

**Examples:**

Input:N = 2Output:120Explanation:

The second 120-gonol number is 120.Input:N = 3Output:357

**Approach:** The N-th 120-gon number is given by the formula:

- Nth term of s sided polygon =

- Therefore Nth term of 120 sided polygon is

Below is the implementation of the above approach:

## C++

`// C++ implementation for above approach` `#include <bits/stdc++.h>` `using` `namespace` `std;` `// Function to find the ` `// nth 120-gon Number` `int` `gonNum120(` `int` `n)` `{` ` ` `return` `(118 * n * n - 116 * n) / 2;` `}` `// Driver Code` `int` `main()` `{` ` ` `int` `n = 3;` ` ` `cout << gonNum120(n);` ` ` `return` `0;` `}` |

## Java

`// Java program for above approach` `class` `GFG{` `// Function to find the` `// nth 120-gon Number` `static` `int` `gonNum120(` `int` `n)` `{` ` ` `return` `(` `118` `* n * n - ` `116` `* n) / ` `2` `;` `}` `// Driver code` `public` `static` `void` `main(String[] args)` `{` ` ` `int` `n = ` `3` `;` ` ` `System.out.print(gonNum120(n));` `}` `}` `// This code is contributed by shubham` |

## Python3

`# Python3 implementation for above approach` `# Function to find the` `# nth 120-gon Number` `def` `gonNum120(n):` ` ` `return` `(` `118` `*` `n ` `*` `n ` `-` `116` `*` `n) ` `/` `/` `2` `;` `# Driver Code` `n ` `=` `3` `;` `print` `(gonNum120(n));` `# This code is contributed by Code_Mech` |

## C#

`// C# program for above approach` `using` `System;` `class` `GFG{` `// Function to find the` `// nth 120-gon Number` `static` `int` `gonNum120(` `int` `n)` `{` ` ` `return` `(118 * n * n - 116 * n) / 2;` `}` `// Driver code` `public` `static` `void` `Main(String[] args)` `{` ` ` `int` `n = 3;` ` ` `Console.Write(gonNum120(n));` `}` `}` `// This code is contributed by sapnasingh4991` |

## Javascript

`<script>` `// JavaScript implementation for above approach` `// Function to find the ` `// nth 120-gon Number` `function` `gonNum120(n)` `{` ` ` `return` `(118 * n * n - 116 * n) / 2;` `}` `// Driver Code` `var` `n = 3;` `document.write(gonNum120(n));` `</script>` |

**Output:**

357

**Reference:** https://en.wikipedia.org/wiki/120-gon

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