Tetracontagon Number
Last Updated :
22 Jun, 2021
Given a number N, the task is to find Nth Tetracontagon number.
A Tetracontagon number is class of figurate number. It has 40 – sided polygon called tetracontagon. The N-th tetracontagon number count’s the 40 number of dots and all others dots are surrounding with a common sharing corner and make a pattern. The first few tetracontagonol numbers are 1, 40, 117, 232 …
Examples:
Input: N = 2
Output: 40
Explanation:
The second tetracontagonol number is 40.
Input: N = 3
Output: 117
Approach: The N-th tetracontagon number is given by the formula:
- Nth term of s sided polygon =
- Therefore Nth term of 40 sided polygon is
Below is the implementation of the above approach:
C++
#include <bits/stdc++.h>
using namespace std;
int tetracontagonNum( int n)
{
return (38 * n * n - 36 * n) / 2;
}
int main()
{
int n = 3;
cout << "3rd tetracontagon Number is = "
<< tetracontagonNum(n);
return 0;
}
|
C
#include <stdio.h>
#include <stdlib.h>
int tetracontagonNum( int n)
{
return (38 * n * n - 36 * n) / 2;
}
int main()
{
int n = 3;
printf ( "3rd tetracontagon Number is = %d" ,
tetracontagonNum(n));
return 0;
}
|
Java
import java.util.*;
class GFG {
static int tetracontagonNum( int n)
{
return ( 38 * n * n - 36 * n) / 2 ;
}
public static void main(String[] args)
{
int n = 3 ;
System.out.println( "3rd tetracontagon Number is = " +
tetracontagonNum(n));
}
}
|
Python3
def tetracontagonNum(n):
return ( 38 * n * n - 36 * n) / / 2
n = 3
print ( "3rd tetracontagon Number is = " ,
tetracontagonNum(n))
|
C#
using System;
class GFG {
static int tetracontagonNum( int n)
{
return (38 * n * n - 36 * n) / 2;
}
public static void Main( string [] args)
{
int n = 3;
Console.Write( "3rd tetracontagon Number is = " +
tetracontagonNum(n));
}
}
|
Javascript
<script>
function tetracontagonNum( n)
{
return (38 * n * n - 36 * n) / 2;
}
let n = 3;
document.write( "3rd tetracontagon Number is " + tetracontagonNum(n));
</script>
|
Output: 3rd tetracontagon Number is = 117
Time Complexity: O(1)
Auxiliary Space: O(1)
Reference: https://en.wikipedia.org/wiki/Tetracontagon
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