Heptadecagonal number

Given a number n, the task is to find the nth heptadecagonal number .
A heptadecagonal number is class of figurate number. It has seventeen sided polygon called heptadecagon. The n-th heptadecagonal number count’s the seventeen number of dots and all others dots are surrounding with a common sharing corner and make a pattern.

Examples:

Input : 5
Output :155

Input :9
Output :549

Heptadecagonal number
Formula to calculate nth heptadecagonal number:

  \begin{math}  Hp_{n}=(15n^2-13n)/2 \end{math}  

C++

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// C++ program to find Nth
// heptadecagonal number
#include <iostream>
using namespace std;
  
// Function to calculate heptadecagonal
// number
int heptadecagonalNum(long int n)
{
    return ((15 * n * n) - 13 * n) / 2;
}
  
// Driver Code
int main()
{
    long int n = 3;
    cout << n << "th Heptadecagonal number : ";
    cout << heptadecagonalNum(n);
    cout << endl;
    n = 8;
    cout << n << "th Heptadecagonal number : ";
    cout << heptadecagonalNum(n);
  
    return 0;
}

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Java

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// Java program to find Nth heptadecagonal number
import java.io.*;
  
class GFG {
      
    // Function to calculate heptadecagonal
    // number
    static long heptadecagonalNum(long n)
    {
        return ((15 * n * n) - 13 * n) / 2;
    }
      
    // Driver Code
    public static void main (String[] args)
    {
        long n = 3;
        System.out.print( n + "th Heptadecagonal" 
                                 + " number : ");
        System.out.println( heptadecagonalNum(n));
          
        n = 8;
        System.out.print( n + "th Heptadecagonal"
                                 + " number : ");
        System.out.print( heptadecagonalNum(n));
    }
}
  
// This code is contributed by anuj_67.

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Python3

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# Python program to find Nth
# heptadecagonal number
  
# Function to calculate
# heptadecagonal number
def heptadecagonalNum(n):
  
    # Formula to calculate nth
    # heptadecagonal number
    return ((15 * n * n) - 13 * n) // 2
  
  
# Driver Code
n = 3
print("%sth Heptadecagonal number : " %n,
                    heptadecagonalNum(n))
n = 8
print("%sth Heptadecagonal number: " %n,
                    heptadecagonalNum(n))
                      
                      
# This code is contributed by ajit                 

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C#

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// C# program to find Nth 
// heptadecagonal number
using System;
class GFG {
      
    // Function to calculate 
    // heptadecagonal number
    static long heptadecagonalNum(long n)
    {
        return ((15 * n * n) - 
                  13 * n) / 2;
    }
      
    // Driver Code
    public static void Main ()
    {
        long n = 3;
        Console.Write( n + "th Heptadecagonal"
                                + " number : ");
        Console.WriteLine( heptadecagonalNum(n));
          
        n = 8;
        Console.Write( n + "th Heptadecagonal"
                                + " number : ");
        Console.WriteLine( heptadecagonalNum(n));
    }
}
  
// This code is contributed by anuj_67.

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PHP

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<?php
// PHP program to find Nth
// heptadecagonal number
  
// Function to calculate heptadecagonal
// number
function heptadecagonalNum( $n)
{
    return ((15 * $n * $n) - 
               13 * $n) / 2;
}
  
    // Driver Code
    $n = 3;
    echo $n , "th Heptadecagonal number : ";
    echo heptadecagonalNum($n);
    echo "\n";
    $n = 8;
    echo $n , "th Heptadecagonal number : ";
    echo heptadecagonalNum($n);
  
// This code is contributed by anuj_67.
?>

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Output

3th Heptadecagonal number : 48
8th Heptadecagonal number : 428

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



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