Given a number n, the task is to find the nth Icosagonal number.
An Icosagonal number is the 20-gon is a twenty-sided polygon. The number derived from the figurative class. There are different pattern series number in this number. The dots are countable, arrange in a specific way of position and create a diagram. All the dots have a common dots points, all others dots are connected to this points and except this common point the dots connected to their i-th dots with their respective successive layer.
Examples :
Input : 3
Output :57
Input :8
Output :512
Formula for nth icosagonal number:
// C++ program to find // nth Icosagonal number #include <bits/stdc++.h> using namespace std;
// Function to calculate Icosagonal number int icosagonal_poly( long int n)
{ // Formula for finding
// nth Icosagonal number
return (18 * n * n - 16 * n) / 2;
} // Drivers code int main()
{ long int n = 7;
cout << n << "th Icosagonal number :"
<< icosagonal_poly(n);
return 0;
} |
// C program to find // nth Icosagonal number #include <stdio.h> // Function to calculate Icosagonal number int icosagonal_poly( long int n)
{ // Formula for finding
// nth Icosagonal number
return (18 * n * n - 16 * n) / 2;
} // Drivers code int main()
{ long int n = 7;
printf ( "%ldth Icosagonal number : %d" ,n,icosagonal_poly(n));
return 0;
} |
// Java program to find // nth Icosagonal number import java.io.*;
class GFG {
// Function to calculate Icosagonal number static int icosagonal_poly( int n)
{ // Formula for finding
// nth Icosagonal number
return ( 18 * n * n - 16 * n) / 2 ;
} // Drivers code public static void main (String[] args) {
int n = 7 ;
System.out.print (n + "th Icosagonal number :" );
System.out.println(icosagonal_poly(n));
}
} // This code is contributed by aj_36 |
# Python 3 program to find # nth Icosagonal number # Function to calculate # Icosagonal number def icosagonal_poly(n) :
# Formula for finding
# nth Icosagonal number
return ( 18 * n * n -
16 * n) / / 2
# Driver Code if __name__ = = '__main__' :
n = 7
print (n, "th Icosagonal number : " ,
icosagonal_poly(n))
# This code is contributed m_kit |
// C# program to find // nth Icosagonal number using System;
class GFG
{ // Function to calculate // Icosagonal number static int icosagonal_poly( int n)
{ // Formula for finding
// nth Icosagonal number
return (18 * n * n -
16 * n) / 2;
} // Driver code static public void Main ()
{ int n = 7;
Console.Write(n + "th Icosagonal " +
"number :" );
Console.WriteLine(icosagonal_poly(n)); } } // This code is contributed by ajit |
<?php // PHP program to find // nth Icosagonal number // Function to calculate // Icosagonal number function icosagonal_poly( $n )
{ // Formula for finding
// nth Icosagonal number
return (18 * $n *
$n - 16 * $n ) / 2;
} // Driver Code $n = 7;
echo $n , "th Icosagonal number :" ,
icosagonal_poly( $n );
// This code is contributed by ajit ?> |
<script> // Javascript program to find nth Icosagonal number
// Function to calculate
// Icosagonal number
function icosagonal_poly(n)
{
// Formula for finding
// nth Icosagonal number
return (18 * n * n - 16 * n) / 2;
}
let n = 7;
document.write(n + "th Icosagonal number :" );
document.write(icosagonal_poly(n));
</script> |
Output :
7th Icosagonal number :385
Time Complexity: O(1)
Auxiliary Space: O(1)
Reference: https://en.wikipedia.org/wiki/Polygonal_number