Given a number N, the task is to find Nth Icosioctagon number.
An Icosioctagon number is class of figurate number. It has 28 – sided polygon called icosikaioctagon. The N-th icosikaioctagonal number count’s the 28 number of dots and all others dots are surrounding with a common sharing corner and make a pattern. The first few icosikaioctagonol numbers are 1, 28, 81, 160 …
Examples:
Input: N = 2
Output: 28
Explanation:
The second icosikaioctagonol number is 28.
Input: N = 3
Output: 81
Approach: The N-th icosikaioctagonal number is given by the formula:
- Nth term of s sided polygon =
- Therefore Nth term of 28 sided polygon is
Below is the implementation of the above approach:
C++
// C++ program for above approach#include <iostream>using namespace std;// Finding the nth icosikaioctagonal numberint icosikaioctagonalNum(int n){ return (26 * n * n - 24 * n) / 2;}// Driver codeint main(){ int n = 3; cout << "3rd icosikaioctagonal Number is = " << icosikaioctagonalNum(n); return 0;}// This code is contributed by shubhamsingh10 |
C
// C program for above approach#include <stdio.h>#include <stdlib.h>// Finding the nth icosikaioctagonal Numberint icosikaioctagonalNum(int n){ return (26 * n * n - 24 * n) / 2;}// Driver program to test above functionint main(){ int n = 3; printf("3rd icosikaioctagonal Number is = %d", icosikaioctagonalNum(n)); return 0;} |
Java
// Java program for above approach class GFG{ // Finding the nth icosikaioctagonal number public static int icosikaioctagonalNum(int n) { return (26 * n * n - 24 * n) / 2; } // Driver codepublic static void main(String[] args){ int n = 3; System.out.println("3rd icosikaioctagonal Number is = " + icosikaioctagonalNum(n));}}// This code is contributed by divyeshrabadiya07 |
Python3
# Python3 program for above approach # Finding the nth icosikaioctagonal Number def icosikaioctagonalNum(n): return (26 * n * n - 24 * n) // 2# Driver Coden = 3print("3rd icosikaioctagonal Number is = ", icosikaioctagonalNum(n)) # This code is contributed by divyamohan123 |
C#
// C# program for above approach using System;class GFG{ // Finding the nth icosikaioctagonal number public static int icosikaioctagonalNum(int n) { return (26 * n * n - 24 * n) / 2; } // Driver codepublic static void Main(){ int n = 3; Console.Write("3rd icosikaioctagonal Number is = " + icosikaioctagonalNum(n));}}// This code is contributed by Code_Mech |
Javascript
<script>// JavaScript program for above approach// Finding the nth icosikaioctagonal numberfunction icosikaioctagonalNum(n){ return (26 * n * n - 24 * n) / 2;}// Driver codevar n = 3;document.write("3rd icosikaioctagonal Number is = " + icosikaioctagonalNum(n));</script> |
Output:
3rd icosikaioctagonal Number is = 81
Time Complexity: O(1)
Auxiliary Space: O(1)
Reference: https://en.wikipedia.org/wiki/Icosioctagon
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