Enneadecagonal number

Given a number n, the task is to find the nth Enneadecagonal number.
An Enneadecagonal number is a nineteen-sided polygon in mathematics. It belongs to a class of figurative number. The number contains the number of dots and the dots are arranged in a pattern or series. An Enneadecagonal number is also known as nonadecagon. The dots have common points and all other dots are arrange in the successive layer.

Examples :

Input : 4
Output :106

Input :10
Output :775

Enneadecagonal number
Formula to find nth Enneadecagonal number :

  \begin{math}  Ed_{n}=((17n^2)-15n)/2 \end{math}  

C++

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// C++ program to find
// nth Enneadecagonal number
#include <bits/stdc++.h>
using namespace std;
  
// Function to calculate 
// Enneadecagonal number
int nthEnneadecagonal(long int n)
{
    // Formula for finding
    // nth Enneadecagonal number
    return (17 * n * n - 15 * n) / 2;
}
  
// Drivers code
int main()
{
    long int n = 6;
    cout << n << "th Enneadecagonal number :" << nthEnneadecagonal(n);
    return 0;
}

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Java

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// Java program to find
// nth Enneadecagonal number
import java.io.*;
  
class GFG {
  
    // Function to calculate 
    // Enneadecagonal number
    static int nthEnneadecagonal(int n)
    {
          
        // Formula for finding
        // nth Enneadecagonal number
        return (17 * n * n - 15 * n) / 2;
    }
      
    // Driver Code
    public static void main (String[] args)
    {
          
        int n = 6;
        System.out.print(n + "th Enneadecagonal number :");
      
        System.out.println( nthEnneadecagonal(n));
    }
}
  
// This code is contributed by m_kit.

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Python3

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# Program to find nth
# Enneadecagonal number
  
def nthEnneadecagonal(n) :
      
    # Formula to calculate nth
    # Enneadecagonal number
    return (17 * n * n - 15 * n) // 2
  
# Driver Code
if __name__ == '__main__' :
          
    n = 6
    print(n,"th Enneadecagonal number :"
                , nthEnneadecagonal(n))
  
# This code is contributed  by Ajit

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C#

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// C# program to find
// nth Enneadecagonal number
using System;
  
class GFG
{
    // Function to calculate 
    // Enneadecagonal number
    static int nthEnneadecagonal(int n)
    {
          
    // Formula for finding
    // nth Enneadecagonal number
    return (17 * n * n - 15 * n) / 2;
    }
      
    // Driver Code
    static public void Main ()
    {
    int n = 6;
    Console.Write(n + "th Enneadecagonal number :");
      
    Console.WriteLine( nthEnneadecagonal(n));
    }
}
  
// This code is contributed by aj_36 

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PHP

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<?php
// PHP program to find
// nth Enneadecagonal number
  
// Function to calculate 
// Enneadecagonal number
function nthEnneadecagonal($n)
{
    // Formula for finding
    // nth Enneadecagonal number
    return (17 * $n * $n
            15 * $n) / 2;
}
  
// Driver Code
$n = 6;
echo $n , "th Enneadecagonal number :" ,
                  nthEnneadecagonal($n);
  
// This code is contributed by ajit
?>

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Output :

6th Enneadecagonal number :261

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



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Improved By : jit_t