Chiliagon Number

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

A chiliagon number is class of figurate number. It has 1000 – sided polygon called chiliagon. The N-th chiliagon number count’s the 1000 number of dots and all others dots are surrounding with a common sharing corner and make a pattern. The first few chiliagonol numbers are 1, 1000, 2997, 5992 …

Examples:

Input: N = 2 
Output: 1000 
Explanation:
The second chiliagonol number is 1000. 
Input: N = 3 
Output: 2997

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

• Nth term of s sided polygon = 
• Therefore Nth term of 1000 sided polygon is
  

Below is the implementation of the above approach: 

C++

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

// Finding the nth chiliagon Number
int chiliagonNum(int n)
{
    return (998 * n * n - 996 * n) / 2;
}

// Driver Code
int main()
{
    int n = 3;
    cout <<"3rd chiliagon Number is = "
         << chiliagonNum(n);

    return 0;
}

// This code is contributed by shivanisinghss2110

C

// C program for above approach
#include <stdio.h>
#include <stdlib.h>

// Finding the nth chiliagon Number
int chiliagonNum(int n)
{
    return (998 * n * n - 996 * n) / 2;
}

// Driver program to test above function
int main()
{
    int n = 3;
    printf("3rd chiliagon Number is = %d",
           chiliagonNum(n));

    return 0;
}

Java

// Java program for the above approach
class GFG{

// Finding the nth chiliagon number
static int chiliagonNum(int n)
{
    return (998 * n * n - 996 * n) / 2;
}

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

// This code is contributed by rutvik_56

Python3

# Python3 program for above approach

# Finding the nth chiliagon Number
def chiliagonNum(n):

    return (998 * n * n - 996 * n) // 2;

# Driver Code
n = 3;
print("3rd chiliagon Number is = ",
                  chiliagonNum(n));

# This code is contributed by Akanksha_Rai

C#

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

// Finding the nth chiliagon number
static int chiliagonNum(int n)
{
    return (998 * n * n - 996 * n) / 2;
}

// Driver code
public static void Main()
{
    int n = 3;
    Console.Write("3rd chiliagon Number is = " +
                               chiliagonNum(n));
}
}

// This code is contributed by Akanksha_Rai

Javascript

<script>

// javascript program for above approach


// Finding the nth chiliagon Number
function chiliagonNum( n)
{
    return (998 * n * n - 996 * n) / 2;
}

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

// This code contributed by gauravrajput1

</script>

Output:

3rd chiliagon Number is = 2997

Time Complexity: O(1)

Auxiliary Space: O(1)

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