Centered Octadecagonal Number
Given a number n, find the nth Centered Octadecagonal number.
The Centered Octadecagonal Number represents a dot in the center and others dot are arranged around it in successive layers of octadecagon(18 sided polygon).
Examples :
Input : 2 Output : 19 Input : 6 Output : 271
In mathematics, Centered Octadecagonal number for n-th term is given by:
Below is the basic implementation of the above idea:
C++
// C++ Program to find the // nth centered octadecagonal // number #include <bits/stdc++.h> using namespace std; // centered octadecagon function int center_octadecagon_num( long int n) { // Formula to calculate nth // centered octadecagonal number return 9 * n * n - 9 * n + 1; } // Driver Code int main() { long int n = 3; cout << n << "th centered octadecagonal number : " << center_octadecagon_num(n); cout << endl; n = 13; cout << n << "th centered octadecagonal number : " << center_octadecagon_num(n); return 0; } |
C
// C Program to find the // nth centered octadecagonal // number #include <stdio.h> // centered octadecagon function int center_octadecagon_num( long int n) { // Formula to calculate nth // centered octadecagonal number return 9 * n * n - 9 * n + 1; } // Driver Code int main() { long int n = 3; printf ( "%ldth centered octadecagonal number : %d\n" ,n,center_octadecagon_num(n)); n = 13; printf ( "%ldth centered octadecagonal number : %d\n" ,n,center_octadecagon_num(n)); return 0; } // This code is contributed by kothavvsaakash. |
Java
// Java Program to find the // nth centered octadecagonal // number import java.io.*; class GFG { // centered octadecagon function static int center_octadecagon_num( int n) { // Formula to calculate nth // centered octadecagonal number return 9 * n * n - 9 * n + 1 ; } // Driver Code public static void main (String[] args) { int n = 3 ; System.out.print(n + "th centered " + "octadecagonal number : " ); System.out.println(center_octadecagon_num(n)); n = 13 ; System.out.print(n + "th centered " + "octadecagonal number : " ); System.out.println(center_octadecagon_num(n)); } } // This code is contributed by ajit |
Python3
# Program to find nth # centered octadecagonal number # Centered octadecagonal # number function def center_octadecagon_num(n) : # Formula to calculate # nth centered octadecagonal # number & return it # into main function. return ( 9 * n * n - 9 * n + 1 ) # Driver Code if __name__ = = '__main__' : n = 3 print (n, "rd centered octadecagonal " + "number : " , center_octadecagon_num(n)) n = 13 print (n, "th centered octadecagonal " + "number : " , center_octadecagon_num(n)) # This code is contributed # by akt_mit |
C#
// C# Program to find the // nth centered octadecagonal // number using System; class GFG { // centered octadecagon function static int center_octadecagon_num( int n) { // Formula to calculate nth // centered octadecagonal number return 9 * n * n - 9 * n + 1; } // Driver Code static public void Main () { int n = 3; Console.Write( n + "th centered " + "octadecagonal number : " ); Console.WriteLine( center_octadecagon_num(n)); n = 13; Console.Write( n + "th centered " + "octadecagonal number : " ); Console.WriteLine(center_octadecagon_num(n)); } } // This code is contributed by aj_36. |
PHP
<?php // PHP Program to find the // nth centered octadecagonal // number // centered octadecagon function function center_octadecagon_num( $n ) { // Formula to calculate nth // centered octadecagonal number return (9 * $n * $n - 9 * $n + 1); } // Driver Code $n = 3; echo $n , "th centered octadecagonal " . "number : " , center_octadecagon_num( $n ); echo "\n" ; $n = 13; echo $n , "th centered octadecagonal " . "number : " , center_octadecagon_num( $n ); // This code is contributed by m_kit ?> |
Javascript
<script> // Javascript program to find the // nth centered octadecagonal // number // centered octadecagon function function center_octadecagon_num(n) { // Formula to calculate nth // centered octadecagonal number return 9 * n * n - 9 * n + 1; } // Driver Code var n = 3; document.write(n + "th centered " + "octadecagonal number : " ); document.write(center_octadecagon_num(n) + "<br>" ); n = 13; document.write(n + "th centered " + "octadecagonal number : " ); document.write(center_octadecagon_num(n)); // This code is contributed by Kirti </script> |
Output :
3th centered octadecagonal number : 55 13th centered octadecagonal number : 1405
Time Complexity: O(1)
Auxiliary Space: O(1)