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Concentric Hexagonal Numbers
• Last Updated : 14 Apr, 2021

The following numbers form the concentric hexagonal sequence :
0, 1, 6, 13, 24, 37, 54, 73, 96, 121, 150 ……
The number sequence forms a pattern with concentric hexagons, and the numbers denote the number of points required after the n-th stage of the pattern. Examples:

Input : N = 3
Output : 13

Input : N = 4
Output : 24

Approach :
The above series can be referred from Concentric Hexagonal Numbers.
Nth term of the series is 3*n2/2

Below is the implementation of the above approach :

## C++

 `// CPP program to find nth concentric hexagon number``#include ``using` `namespace` `std;` `// Function to find nth concentric hexagon number``int` `concentric_Hexagon(``int` `n)``{``    ``return` `3 * ``pow``(n, 2) / 2;``}` `// Driver code``int` `main()``{``    ``int` `n = 3;` `    ``// Function call``    ``cout << concentric_Hexagon(n);` `    ``return` `0;``}`

## Java

 `// Java program to find``// nth concentric hexagon number``class` `GFG``{``    ` `    ``// Function to find``    ``// nth concentric hexagon number``    ``static` `int` `concentric_Haxagon(``int` `n)``    ``{``        ``return` `3` `* (``int``)Math.pow(n, ``2``) / ``2``;``    ``}``    ` `    ``// Driver Code``    ``public` `static` `void` `main (String[] args)``    ``{``        ``int` `n = ``3``;``        ` `        ``// Function call``        ``System.out.println(concentric_Haxagon(n));``    ``}``}` `// This code is contributed by``// sanjeev2552`

## Python3

 `# Python3 program to find``# nth concentric hexagon number`` ` `# Function to find``# nth concentric hexagon number``def` `concentric_Hexagon(n):` `    ``return` `3` `*` `pow``(n, ``2``) ``/``/` `2` `# Driver code``n ``=` `3` `# Function call``print``(concentric_Hexagon(n))`` ` `# This code is contributed by Mohit Kumar`

## C#

 `// C# program to find nth concentric hexagon number``using` `System;``class` `GFG``{` `// Function to find nth concentric hexagon number``static` `int` `concentric_Hexagon(``int` `n)``{``    ``return` `3 * (``int``)Math.Pow(n, 2) / 2;``}` `// Driver code``public` `static` `void` `Main()``{``    ``int` `n = 3;` `    ``// Function call``    ``Console.WriteLine(concentric_Hexagon(n));``}``}` `// This code is contributed by Nidhi`

## Javascript

 ``
Output:
`13`

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