Given a number n, find the nth Centered decagonal number .
A Centered Decagonal Number is centered figurative number that represents a decagon with dot in center and all other dot surrounding it in successive decagonal form. Source[Wiki].
The first few Centered Decagonal Numbers are :
1, 11, 31, 61, 101, 151, 211, 281, 361, 451, 551, 661…………
Examples :
Input : 3 Output : 31 Input : 6 Output : 151
In mathematics centered decagonal number for n-th term is given by :
Below is the basic implementation of the above idea.
C++
// Program to find nth// centered decagonal // number#include <bits/stdc++.h>using namespace std;// Centered decagonal// number functionint centereddecagonalnum(int n){ // Formula to calculate nth // centered decagonal number & // return it into main function. return (5 * n * n + 5 * n + 1);}// Driver Codeint main(){ int n = 5; cout << n << "th centered decagonal" << "number: "; cout << centereddecagonalnum(n); cout << endl; n = 9; cout << n << "th centered decagonal" << "number: "; cout << centereddecagonalnum(n); return 0;} |
C
// C Program to find nth// centered decagonal // number#include <stdio.h>// Centered decagonal// number functionint centereddecagonalnum(int n){ // Formula to calculate nth // centered decagonal number & // return it into main function. return (5 * n * n + 5 * n + 1);}// Driver Codeint main(){ int n = 5; printf("%dth centered decagonal number: ",n); printf("%d\n",centereddecagonalnum(n)); n = 9; printf("%dth centered decagonal number: ",n); printf("%d\n",centereddecagonalnum(n)); return 0;}// This code is contributed by kothavvsaakash. |
Java
// Java Program to find nth// centered decagonal numberimport java.io.*;class GFG { // Centered decagonal // number function static int centereddecagonalnum(int n) { // Formula to calculate nth // centered decagonal number & // return it into main function. return (5 * n * n + 5 * n + 1); } // Driver Code public static void main (String[] args) { int n = 5; System.out.print(n + "th centered " + "decagonal number: "); System.out.println(centereddecagonalnum(n)); n = 9; System.out.print(n + "th centered " + "decagonal number: "); System.out.println(centereddecagonalnum(n)); }}// This code is contributed by m_kit |
Python3
# Program to find nth# centered decagonal number# Centered decagonal# number functiondef centereddecagonalnum(n) : # Formula to calculate # nth centered decagonal # number & return it # into main function. return (5 * n * n + 5 * n + 1)# Driver Codeif __name__ == '__main__' : n = 5 print(n,"th centered decagonal " + "number : ", centereddecagonalnum(n)) n = 9 print(n,"th centered decagonal " + "number : ", centereddecagonalnum(n)) # This code is contributed by m_kit |
C#
// Program to find nth// centered decagonal // numberusing System;class GFG{// Centered decagonal// number functionstatic int centereddecagonalnum(int n){ // Formula to calculate nth // centered decagonal number & // return it into main function. return (5 * n * n + 5 * n + 1);}// Driver Codestatic public void Main (){int n = 5;Console.Write(n + "th centered decagonal"+ "number: ");Console.WriteLine(centereddecagonalnum(n));n = 9;Console.Write(n + "th centered decagonal"+ "number: ");Console.WriteLine(centereddecagonalnum(n));}}// This code is contributed by aj_36 |
PHP
<?php// Program to find nth// centered decagonal number// Centered decagonal// number functionfunction centereddecagonalnum($n){ // Formula to calculate // nth centered decagonal // number & return it // into main function. return (5 * $n * $n + 5 * $n + 1);}// Driver Code$n = 5;echo $n , "th centered decagonal", "number: ";echo centereddecagonalnum($n);echo "\n";$n = 9;echo $n , "th centered decagonal", "number: ";echo centereddecagonalnum($n);// This code is contributed by ajit?> |
Javascript
<script>// Javascript Program to find nth// centered decagonal number// Centered decagonal// number functionfunction centereddecagonalnum(n){ // Formula to calculate nth // centered decagonal number & // return it into main function. return (5 * n * n + 5 * n + 1);}// Driver Code var n = 5;document.write(n + "th centered " + "decagonal number: ");document.write(centereddecagonalnum(n) + "<br>");n = 9;document.write(n + "th centered " + "decagonal number: ");document.write(centereddecagonalnum(n));// This code is contributed by Kirti </script> |
Output
5th centered decagonalnumber: 151 9th centered decagonalnumber: 451
Time Complexity: O(1)
Auxiliary Space: O(1)
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