Icosidigonal number
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++
// 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
// 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
// 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
# 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#
// 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 // 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 ?> |
Javascript
<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