# Centered tridecagonal number

Given a number n, the task is to find the nth Centered Tridecagonal Number.

A Centered tridecagonal number represents a dot at the center and other dots surrounding the center dot
in the successive tridecagonal(13 sided polygon) layer.

Examples :

Input : 2
Output : 14

Input : 9
Output : 469

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

Formula for nth Centered tridecagonal number:

```
```

## C++

 `// C++ Program to find nth ` `// centered tridecagonal number ` `#include ` `using` `namespace` `std; ` ` `  `// Function to find nth centered ` `// tridecagonal number ` `int` `centeredTridecagonalNum(``long` `int` `n) ` `{ ` `    ``// Formula to calculate nth ` `    ``// centered tridecagonal number ` `    ``return` `(13 * n * (n - 1) + 2) / 2; ` `} ` ` `  `// Drivers code ` `int` `main() ` `{ ` `    ``long` `int` `n = 3; ` `    ``cout << centeredTridecagonalNum(n); ` `    ``cout << endl; ` `    ``n = 10; ` `    ``cout << centeredTridecagonalNum(n); ` ` `  `    ``return` `0; ` `} `

## Java

 `// Java Program to find nth ` `// centered tridecagonal number ` `import` `java.io.*; ` ` `  `class` `GFG  ` `{ ` ` `  `// Function to find nth centered ` `// tridecagonal number ` `static` `long` `centeredTridecagonalNum(``long` `n) ` `{ ` `    ``// Formula to calculate nth ` `    ``// centered tridecagonal number ` `    ``return` `(``13` `* n * (n - ``1``) + ``2``) / ``2``; ` `} ` ` `  `// Driver Code ` `public` `static` `void` `main (String[] args)  ` `{ ` `    ``long` `n = ``3``; ` `    ``System.out.println(centeredTridecagonalNum(n)); ` `    ``n = ``10``; ` `    ``System.out.println(centeredTridecagonalNum(n)); ` `} ` `} ` ` `  `// This code is contributed by anuj_67. `

## Python3

 `# Program to find nth centered  ` `# tridecagonal number ` ` `  `# Function to find centered ` `# tridecagonal number ` `def` `centeredTridecagonalNum(n) : ` `     `  `    ``# Formula to calculate nth ` `    ``# centered tridecagonal number ` `    ``return` `(``13` `*` `n ``*`  `           ``(n ``-` `1``) ``+` `2``) ``/``/` `2` ` `  `# Driver Code ` `if` `__name__ ``=``=` `'__main__'` `: ` `         `  `    ``n ``=` `3` `    ``print``(centeredTridecagonalNum(n)) ` `    ``n ``=` `10` `    ``print``(centeredTridecagonalNum(n)) ` `                 `  `# This code is contributed ` `# by akt_mit `

## C#

 `// C# Program to find nth ` `// centered tridecagonal number ` `using` `System; ` ` `  `class` `GFG  ` `{ ` ` `  `// Function to find nth centered ` `// tridecagonal number ` `static` `long` `centeredTridecagonalNum(``long` `n) ` `{ ` `    ``// Formula to calculate nth ` `    ``// centered tridecagonal number ` `    ``return` `(13 * n * (n - 1) + 2) / 2; ` `} ` ` `  `// Driver Code ` `public` `static` `void` `Main ()  ` `{ ` `    ``long` `n = 3; ` `    ``Console.WriteLine(centeredTridecagonalNum(n)); ` `    ``n = 10; ` `    ``Console.WriteLine(centeredTridecagonalNum(n)); ` `} ` `} ` ` `  `// This code is contributed by anuj_67. `

## PHP

 ` `

Output :

```40
586
```

Reference: http://oeis.org/wiki/Figurate_numbers

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