Heptacontadigon number

Given a number N, the task is to find N^th Heptacontadigon number.

A Heptacontadigon Number is a class of figurate numbers. It has a 72-sided polygon called Heptacontadigon. The N-th Heptacontadigon number count’s the 72 number of dots and all other dots are surrounding with a common sharing corner and make a pattern. The first few Heptacontadigonol numbers are 1, 72, 213, 424, …

Examples:

Input: N = 2 
Output: 72 
Explanation:
The second Heptacontadigonol number is 72. 
Input: N = 3 
Output: 213 

Approach: The N-th Heptacontadigon number is given by the formula: 

• N-th term of S sided polygon = 
• Therefore, the N-th term of 72 sided polygon is given by: 
  

Below is the implementation of the above approach:

C++

// C++ program for the above approach
#include <bits/stdc++.h>
using namespace std;

// Function to find the N-th
// Heptacontadigon Number
int HeptacontadigonNum(int N)
{
    return (70 * N * N - 68 * N)
           / 2;
}

// Driver Code
int main()
{
    // Given number N
    int N = 3;

    // Function Call
    cout << HeptacontadigonNum(N);

    return 0;
}

Java

// Java program for the above approach
class GFG{

// Function to find the N-th
// Heptacontadigon Number
static int HeptacontadigonNum(int N)
{
    return (70 * N * N - 68 * N) / 2;
}

// Driver code
public static void main(String[] args)
{
    int N = 3;

    System.out.println(HeptacontadigonNum(N));
}
}

// This code is contributed by Pratima Pandey

Python3

# Python3 program for the above approach

# Function to find the N-th
# Heptacontadigon Number
def HeptacontadigonNum(N):

    return (70 * N * N - 68 * N) // 2;

# Driver Code

# Given number N
N = 3;

# Function Call
print(HeptacontadigonNum(N));

# This code is contributed by Code_Mech

C#

// C# program for the above approach
using System;
class GFG{

// Function to find the N-th
// Heptacontadigon Number
static int HeptacontadigonNum(int N)
{
    return (70 * N * N - 68 * N) / 2;
}

// Driver code
public static void Main()
{
    int N = 3;

    Console.Write(HeptacontadigonNum(N));
}
}

// This code is contributed by Code_Mech

Javascript

<script>

    // JavaScript program for the above approach

    // Function to find the N-th
    // Heptacontadigon Number
    function HeptacontadigonNum(N)
    {
        return parseInt((70 * N * N - 68 * N) / 2, 10);
    }

    // Given number N
    let N = 3;

    // Function Call
    document.write(HeptacontadigonNum(N));

</script>

Output:

213

Time Complexity: O(1)