Given a number n, the task is to find the nth hexadecagonal number.

A Hexadecagonal number is class of figurate number and a perfect squares. It has sixteen sided polygon called hexadecagon or hexakaidecagon. The n-th hexadecagonal number count’s the sixteen number of dots and all others dots are surrounding to its successive layer.

**Examples :**

Input : 2

Output :16Input :7

Output :301

Formula to calculate hexadecagonal number:

## C++

`// C++ program to find Nth ` `// hexadecagon number ` `#include <bits/stdc++.h> ` `using` `namespace` `std; ` ` ` `// Function to calculate hexadecagonal number ` `int` `hexadecagonalNum(` `long` `int` `n) ` `{ ` ` ` `return` `((14 * n * n) - 12 * n) / 2; ` `} ` ` ` `// Drivers Code ` `int` `main() ` `{ ` ` ` `long` `int` `n = 5; ` ` ` `cout << n << ` `"th Hexadecagonal number : "` `; ` ` ` `cout << hexadecagonalNum(n); ` ` ` `cout << endl; ` ` ` `n = 9; ` ` ` `cout << n << ` `"th Hexadecagonal number : "` `; ` ` ` `cout << hexadecagonalNum(n); ` ` ` ` ` `return` `0; ` `} ` |

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## Java

`// Java program to find Nth hexadecagon ` `// number ` `import` `java.io.*; ` ` ` `class` `GFG { ` ` ` ` ` `// Function to calculate hexadecagonal ` ` ` `// number ` ` ` `static` `long` `hexadecagonalNum(` `long` `n) ` ` ` `{ ` ` ` `return` `((` `14` `* n * n) - ` `12` `* n) / ` `2` `; ` ` ` `} ` ` ` ` ` `// Drivers Code ` ` ` `public` `static` `void` `main (String[] args) ` ` ` `{ ` ` ` `long` `n = ` `5` `; ` ` ` `System.out.println( n + ` `"th "` ` ` `+ ` `"Hexadecagonal number : "` ` ` `+ hexadecagonalNum(n)); ` ` ` ` ` `n = ` `9` `; ` ` ` `System.out.println( n + ` `"th "` ` ` `+ ` `"Hexadecagonal number : "` ` ` `+ hexadecagonalNum(n)); ` ` ` `} ` `} ` ` ` `// This code contribued by anuj_67. ` |

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## Python3

`# Python program to find Nth ` `# hexadecagon number ` ` ` `# Function to calculate ` `# hexadecagonal number ` `def` `hexadecagonalNum(n): ` ` ` ` ` `# Formula to calculate nth ` ` ` `# Centered heptagonal number ` ` ` `return` `((` `14` `*` `n ` `*` `n) ` `-` `12` `*` `n) ` `/` `/` `2` ` ` `# Driver Code ` `n ` `=` `5` `print` `(` `"%sth Hexadecagonal number : "` `%` `n, ` ` ` `hexadecagonalNum(n)) ` `n ` `=` `9` `print` `(` `"%sth Hexadecagonal number : "` `%` `n, ` ` ` `hexadecagonalNum(n)) ` ` ` `# This code is contributed by ajit ` |

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## C#

`// C# program to find Nth hexadecagon ` `// number ` `using` `System; ` `class` `GFG { ` ` ` ` ` `// Function to calculate hexadecagonal ` ` ` `// number ` ` ` `static` `long` `hexadecagonalNum(` `long` `n) ` ` ` `{ ` ` ` `return` `((14 * n * n) - 12 * n) / 2; ` ` ` `} ` ` ` ` ` `// Drivers Code ` ` ` `public` `static` `void` `Main () ` ` ` `{ ` ` ` `long` `n = 5; ` ` ` `Console.WriteLine( n + ` `"th "` ` ` `+ ` `"Hexadecagonal number : "` ` ` `+ hexadecagonalNum(n)); ` ` ` ` ` `n = 9; ` ` ` `Console.WriteLine( n + ` `"th "` ` ` `+ ` `"Hexadecagonal number : "` ` ` `+ hexadecagonalNum(n)); ` ` ` `} ` `} ` ` ` `// This code contribued by anuj_67. ` |

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## PHP

`<?php ` `// PHP program to find Nth ` `// hexadecagon number ` ` ` `// Function to calculate ` `// hexadecagonal number ` ` ` `function` `hexadecagonalNum(` `$n` `) ` `{ ` ` ` `return` `((14 * ` `$n` `* ` `$n` `) - 12 * ` `$n` `) / 2; ` `} ` ` ` `// Driver Code ` `$n` `= 5; ` `echo` `$n` `, ` `"th Hexadecagonal number : "` `; ` `echo` `hexadecagonalNum(` `$n` `); ` `echo` `"\n"` `; ` ` ` `$n` `= 9; ` `echo` `$n` `, ` `"th Hexadecagonal number : "` `; ` `echo` `hexadecagonalNum(` `$n` `); ` ` ` `// This code is contributed bu m_kit ` `?> ` |

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**Output :**

5th Hexadecagonal number : 145 9th Hexadecagonal number : 513

Reference: https://en.wikipedia.org/wiki/Polygonal_number

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