Given a number n, the task is to find the nth Icosidigonal number (Isdn).
The polygon has the many gons, depends on their gonal number series. In mathematics, there is a number of gonal numbers and the icosidigonal number is one of them and these numbers have 22 -sided polygon (icosidigon). An icosidigonal number belong to the class of figurative number. They have one common dots points and other dots pattern is arranged in an n-th nested icosidigon pattern.
Examples :
Input : 2
Output :22
Input :6
Output :306
Formula for nth Icosidigonal number:
// C++ program to find nth Icosidigonal // number #include <bits/stdc++.h> using namespace std;
// Function to calculate Icosidigonal number int icosidigonal_num( long int n)
{ // Formula for finding
// nth Icosidigonal number
return (20 * n * n - 18 * n) / 2;
} // Driver function int main()
{ long int n = 4;
cout << n << "th Icosidigonal number :" << icosidigonal_num(n);
cout << endl;
n = 8;
cout << n << "th Icosidigonal number:" << icosidigonal_num(n);
return 0;
} |
// C program to find nth Icosidigonal // number #include <stdio.h> // Function to calculate Icosidigonal number int icosidigonal_num( long int n)
{ // Formula for finding
// nth Icosidigonal number
return (20 * n * n - 18 * n) / 2;
} // Driver function int main()
{ long int n = 4;
printf ( "%ldth Icosidigonal number : %d\n" ,n,icosidigonal_num(n));
n = 8;
printf ( "%ldth Icosidigonal number : %d\n" ,n,icosidigonal_num(n));
return 0;
} // This code is contributed by kothavvsaakash. |
// Java program to find nth // Icosidigonal number import java.io.*;
class GFG
{ // Function to calculate
// Icosidigonal number
static int icosidigonal_num( int n)
{
// Formula for finding
// nth Icosidigonal number
return ( 20 * n * n - 18 * n) / 2 ;
}
// Driver Code public static void main (String[] args)
{ int n = 4 ;
System.out.print (n + "th Icosidigonal number :" );
System.out.println (icosidigonal_num(n));
n = 8 ;
System.out.print (n + "th Icosidigonal number :" );
System.out.println (icosidigonal_num(n));
} } // This code is contributed by ajit |
# python 3 program to find # nth Icosidigonal number # Function to calculate # Icosidigonal number def icosidigonal_num(n) :
# Formula for finding
# nth Icosidigonal number
return ( 20 * n * n -
18 * n) / / 2
# Driver Code if __name__ = = '__main__' :
n = 4
print (n, "th Icosidigonal " +
"number : " ,
icosidigonal_num(n))
n = 8
print (n, "th Icosidigonal " +
"number : " ,
icosidigonal_num(n))
# This code is contributed m_kit |
// C# program to find nth // Icosidigonal number using System;
class GFG
{ // Function to calculate
// Icosidigonal number
static int icosidigonal_num( int n)
{
// Formula for finding
// nth Icosidigonal number
return (20 * n * n -
18 * n) / 2;
}
// Driver Code static public void Main ()
{ int n = 4;
Console.Write(n + "th Icosidigonal " +
"number :" );
Console.WriteLine(icosidigonal_num(n)); n = 8; Console.Write (n + "th Icosidigonal " +
"number :" );
Console.WriteLine(icosidigonal_num(n)); } } // This code is contributed by ajit |
<?php // PHP program to find nth // Icosidigonal number // Function to calculate // Icosidigonal number function icosidigonal_num( $n )
{ // Formula for finding
// nth Icosidigonal number
return (20 * $n * $n - 18 * $n ) / 2;
} // Driver Code $n = 4;
echo $n , "th Icosidigonal number : " ,
icosidigonal_num( $n );
echo "\n" ;
$n = 8;
echo $n , "th Icosidigonal number : " ,
icosidigonal_num( $n );
// This code is contributed by m_kit ?> |
<script> // JavaScript program to find nth Icosidigonal // number // Function to calculate Icosidigonal number function icosidigonal_num(n)
{ // Formula for finding
// nth Icosidigonal number
return parseInt((20 * n * n - 18 * n) / 2);
} // Driver function let n = 4; document.write(n + "th Icosidigonal number :" + icosidigonal_num(n));
document.write( "<br>" );
n = 8; document.write(n + "th Icosidigonal number :" + icosidigonal_num(n));
</script> |
Output :
4th Icosidigonal number :124 8th Icosidigonal number:568
Time Complexity: O(1)
Auxiliary Space: O(1)
Reference: https://en.wikipedia.org/wiki/Polygonal_number