Icosikaiheptagonal Number

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

An icosikaiheptagonal number is a class of figurate numbers. It has 27 – sided polygon called icosikaiheptagon. The N-th icosikaiheptagonal number count’s the 27 number of dots and all other dots are surrounding with a common sharing corner and make a pattern. The first few icosikaiheptagonol numbers are 1, 27, 78, 154 …

Examples:

Input: N = 2 
Output: 27 
Explanation:
The second icosikaiheptagonol number is 27. 
Input: N = 3 
Output: 78 

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

• Nth term of s sided polygon = 
  
• Therefore Nth term of 27 sided polygon is 
  

Below is the implementation of the above approach:

C++

// C++ program to find N-th
// icosikaiheptagonal number
#include <bits/stdc++.h>

using namespace std;
// Function to find the nth
// icosikaiheptagonal Number
int icosikaiheptagonalNum(int n)
{
    return (25 * n * n - 23 * n) / 2;
}

// Driver code
int main()
{
    int n = 3;

    cout << "3rd icosikaiheptagonal Number is "
         << icosikaiheptagonalNum(n);

    return 0;
}

Java

// Java program to find N-th
// icosikaiheptagonal number
class GFG{

// Function to find the nth
// icosikaiheptagonal number
static int icosikaiheptagonalNum(int n)
{
    return (25 * n * n - 23 * n) / 2;
}

// Driver code
public static void main(String[] args)
{
    int n = 3;
    System.out.print("3rd icosikaiheptagonal Number is " +
                                icosikaiheptagonalNum(n));
}
}

// This code is contributed by shubham

Python3

# Python3 program to find N-th
# icosikaiheptagonal number

# Function to find the nth
# icosikaiheptagonal Number
def icosikaiheptagonalNum(n):

    return (25 * n * n - 23 * n) // 2;

# Driver code
n = 3;
print("3rd icosikaiheptagonal Number is ",
                icosikaiheptagonalNum(n));

# This code is contributed by Code_Mech

C#

// C# program to find N-th
// icosikaiheptagonal number
using System;

class GFG{

// Function to find the nth
// icosikaiheptagonal number
static int icosikaiheptagonal(int n)
{
    return (25 * n * n - 23 * n) / 2;
}

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

    Console.Write("3rd icosikaiheptagonal Number is " +
                                icosikaiheptagonal(n));
}
}

// This code is contributed by shivanisinghss2110

Javascript

<script>

// javascript program to find N-th
// icosikaiheptagonal number

// Function to find the nth
// icosikaiheptagonal Number
function icosikaiheptagonalNum( n)
{
    return (25 * n * n - 23 * n) / 2;
}

// Driver code
let n = 3;
    document.write("3rd icosikaiheptagonal Number is "+ icosikaiheptagonalNum(n));

// This code is contributed by todaysgaurav

</script>

Output:

3rd icosikaiheptagonal Number is 78

Time Complexity: O(1)

Auxiliary Space: O(1)

Reference: http://www.2dcurves.com/line/linep.html