Dodecagonal number

Given a number n, find the nth Dodecagonal number.Dodecagonal numbers represent Dodecagonal (A polygon with 12 sides). 
Some of the Dodecagonal numbers are: 
1, 12, 33, 64, 105, 156, 217, 288, 369, 460, 561, 672, 793, 924………………………..
Examples :

Input : n = 4
Output : 64

Input : n = 9
Output : 369

Formula of nth Term of Dodecagonal number :

n-th Dodecagonal number = 5n2 - 4n

Below is the implementation for nth Dodecagonal Number: 

C++

// CPP Program to find the
// nth Dodecagonal number
#include <bits/stdc++.h>
using namespace std;

// function for Dodecagonal
// number
int Dodecagonal_number(int n)
{
    // formula for find Dodecagonal
    // nth term
    return 5 * n * n - 4 * n;
}

// Driver Code
int main()
{

    int n = 7;
    cout << Dodecagonal_number(n) << endl;

    n = 12;
    cout << Dodecagonal_number(n) << endl;

    return 0;
}

C

// C Program to find the
// nth Dodecagonal number
#include <stdio.h>

// function for Dodecagonal
// number
int Dodecagonal_number(int n)
{
    // formula for find Dodecagonal
    // nth term
    return 5 * n * n - 4 * n;
}

// Driver Code
int main()
{

    int n = 7;
    printf("%d\n",Dodecagonal_number(n));

    n = 12;
    printf("%d\n",Dodecagonal_number(n));

    return 0;
}

// This code is contributed by kothavvsaakash

Java

// Java program to find the
// nth Dodecagonal number
import java.util.*;

class GFG
{

    // function for
    // Dodecagonal number
    static int Dodecagonal_number(int n)
    {
        // formula for find
        // Dodecagonal nth term
        return 5 * n * n - 4 * n;
    }

    // Driver Code
    public static void main(String[] args)
    {

    int n = 7;
    System.out.println(Dodecagonal_number(n));

    n = 12;
    System.out.println(Dodecagonal_number(n));

    }
}

// This code is contributed by Anuj_67

Python3

# Python program to find
# nth Dodecagonal number

# Function to calculate
# Dodecagonal number
def Dodecagonal_number(n):

    # Formula to calculate nth
    # Dodecagonal number

    return  5 * n * n - 4 * n

# Driver Code
n = 7
print(Dodecagonal_number(n))

n = 12
print(Dodecagonal_number(n))

# This code is contributed by aj_36.

C#

// C# program to find the nth Dodecagonal
// number
using System;

class GFG {

    // function for Dodecagonal
    // number
    static int Dodecagonal_number(int n)
    {
        // formula for find Dodecagonal
        // nth term
        return 5 * n * n - 4 * n;
    }

    // Driver Code
    static void Main()
    {

        int n = 7;
        Console.WriteLine(Dodecagonal_number(n));

        n = 12;
        Console.WriteLine(Dodecagonal_number(n));

    }
}

// This code is contributed by Anuj_67

PHP

<?php
// PHP Program to find the
// nth Dodecagonal number

// function for Dodecagonal
// number
function Dodecagonal_number($n)
{

    // formula for find Dodecagonal
    // nth term
    return 5 * $n * $n - 4 * $n;
}

// Driver code
    $n = 7;
    echo Dodecagonal_number($n), "\n";

    $n = 12;
    echo Dodecagonal_number($n), "\n";


// This code is contributed by aj_36
?>

Javascript

<script>
// Javascript Program to find the
// nth Dodecagonal number

// function for Dodecagonal
// number
function Dodecagonal_number(n)
{

    // formula for find Dodecagonal
    // nth term
    return 5 * n * n - 4 * n;
}

// Driver Code

let n = 7;
document.write(Dodecagonal_number(n) + "<br>");

n = 12;
document.write(Dodecagonal_number(n) + "<br>");

// This code is contributed by subham348.
</script>

Output :

217
672

Time Complexity: O(1)
Auxiliary Space: O(1)
References: https://en.wikipedia.org/wiki/Dodecagonal_number