Given a number n, the task is to find the nth Hendecagonal number.
A Hendecagonal number is a figurate number that extends the concept of triangular and square numbers to the decagon (Eleven -sided polygon). The nth hendecagonal number counts the number of dots in a pattern of n nested decagons, all sharing a common corner, where the ith hendecagon in the pattern has sides made of i dots spaced one unit apart from each other.
Examples:
Input : 2
Output :11
Input :6
Output :141
Formula for nth hendecagonal number :
C++
// C++ program to find nth// Hendecagonal number#include <bits/stdc++.h>using namespace std;// Function to find// Hendecagonal numberint hendecagonal_num(int n){ // Formula to calculate nth // Hendecagonal number return (9 * n * n - 7 * n) / 2;}// Driver Codeint main(){ int n = 3; cout << n << "rd Hendecagonal number: "; cout << hendecagonal_num(n); cout << endl; n = 10; cout << n << "th Hendecagonal number: "; cout << hendecagonal_num(n); return 0;} |
C
// C program to find nth// Hendecagonal number#include <stdio.h>// Function to find// Hendecagonal numberint hendecagonal_num(int n){ // Formula to calculate nth // Hendecagonal number return (9 * n * n - 7 * n) / 2;}// Driver Codeint main(){ int n = 3; printf("%drd Hendecagonal number: ",n); printf("%d\n",hendecagonal_num(n)); n = 10; printf("%dth Hendecagonal number: ",n); printf("%d\n",hendecagonal_num(n)); return 0;}// This code is contributed by kothavvsaakash. |
Java
// Java program to find nth// Hendecagonal numberimport java.io.*;class GFG{ // Function to find// Hendecagonal numberstatic int hendecagonal_num(int n){ // Formula to calculate nth // Hendecagonal number return (9 * n * n - 7 * n) / 2;}// Driver Codepublic static void main (String[] args){int n = 3;System.out.print(n + "rd Hendecagonal " + "number: ");System.out.println(hendecagonal_num(n));n = 10;System.out.print(n + "th Hendecagonal " + "number: ");System.out.println(hendecagonal_num(n));}}// This code is contributed by ajit |
Python3
# Program to find nth# Hendecagonal number# Function of Hendecagonal # number def hendecagonal_num(n) : # Formula to calculate nth # Hendecagonal number & # return it into main function. return (9 * n * n - 7 * n) // 2# Driver Codeif __name__ == '__main__' : n = 3 print(n,"rd Hendecagonal number : " , hendecagonal_num(n)) n = 10 print(n,"th Hendecagonal number : " , hendecagonal_num(n))# This code is contributed by ajit |
C#
// C# program to find nth// Hendecagonal numberusing System;class GFG{// Function to find// Hendecagonal numberstatic int hendecagonal_num(int n){ // Formula to calculate nth // Hendecagonal number return (9 * n * n - 7 * n) / 2;}// Driver Codestatic public void Main (){ int n = 3; Console.Write(n + "rd Hendecagonal number: "); Console.WriteLine( hendecagonal_num(n)); n = 10; Console.Write(n + "th Hendecagonal number: "); Console.WriteLine( hendecagonal_num(n)); }}// This code is contributed by aj_36 |
PHP
<?php// PHP program to find nth// Hendecagonal number// Function to find// Hendecagonal numberfunction hendecagonal_num($n){ // Formula to calculate nth // Hendecagonal number return (9 * $n * $n - 7 * $n) / 2;}// Driver Code$n = 3;echo $n , "th Hendecagonal number: ";echo hendecagonal_num($n);echo "\n"; $n = 10;echo $n , "th Hendecagonal number: ";echo hendecagonal_num($n);// This code is contributed by m_kit?> |
Javascript
<script> // Javascript program to find nth // Hendecagonal number // Function to find // Hendecagonal number function hendecagonal_num(n) { // Formula to calculate nth // Hendecagonal number return (9 * n * n - 7 * n) / 2; } let n = 3; document.write(n + "rd Hendecagonal number: "); document.write(hendecagonal_num(n) + "</br>"); n = 10; document.write(n + "th Hendecagonal number: "); document.write(hendecagonal_num(n));// This code is contributed by divyesh072019.</script> |
Output :
3th Hendecagonal number: 30 10th Hendecagonal number: 415
Time Complexity: O(1)
Auxiliary Space: O(1)
Reference: https://en.wikipedia.org/wiki/Polygonal_number
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