Given a number N, the task is to find Nth Enneacontagon number.
A Enneacontagon number. is class of figurate number. It has 90 – sided polygon called enneacontagon. The N-th enneacontagon number count’s the 90 number of dots and all others dots are surrounding with a common sharing corner and make a pattern. The first few enneacontagonol numbers are 1, 90, 267, 532 …
Examples:
Input: N = 2
Output: 90
Explanation:
The second enneacontagonol number is 90.
Input: N = 3
Output: 267
Approach: The N-th enneacontagon number is given by the formula:
- Nth term of s sided polygon =
- Therefore Nth term of 90 sided polygon is
Below is the implementation of the above approach:
C++
// C++ program for above approach#include <bits/stdc++.h>using namespace std;// Finding the nth enneacontagon Numberint enneacontagonNum(int n){ return (88 * n * n - 86 * n) / 2;}// Driver Codeint main(){ int n = 3; cout << "3rd enneacontagon Number is = " << enneacontagonNum(n); return 0;}// This code is contributed by Akanksha_Rai |
C
// C program for above approach#include <stdio.h>#include <stdlib.h>// Finding the nth enneacontagon Numberint enneacontagonNum(int n){ return (88 * n * n - 86 * n) / 2;}// Driver program to test above functionint main(){ int n = 3; printf("3rd enneacontagon Number is = %d", enneacontagonNum(n)); return 0;} |
Java
// Java program for above approachclass GFG{// Finding the nth enneacontagon number public static int enneacontagonNum(int n) { return (88 * n * n - 86 * n) / 2; } // Driver code public static void main(String[] args){ int n = 3; System.out.println("3rd enneacontagon Number is = " + enneacontagonNum(n));}}// This code is contributed by divyeshrabadiya07 |
Python3
# Python3 program for above approach # Finding the nth enneacontagon Number def enneacontagonNum(n): return (88 * n * n - 86 * n) // 2# Driver Coden = 3print("3rd enneacontagon Number is = ", enneacontagonNum(n))# This code is contributed by divyamohan123 |
C#
// C# program for above approachusing System;class GFG{// Finding the nth enneacontagon number public static int enneacontagonNum(int n) { return (88 * n * n - 86 * n) / 2; } // Driver code public static void Main(String[] args){ int n = 3; Console.WriteLine("3rd enneacontagon Number is = " + enneacontagonNum(n));}}// This code is contributed by Rajput-Ji |
Javascript
<script>// JavaScript program for above approach// Finding the nth enneacontagon Numberfunction enneacontagonNum(n){ return (88 * n * n - 86 * n) / 2;}// Driver Codevar n = 3;document.write("3rd enneacontagon Number is = " + enneacontagonNum(n));</script> |
Output:
3rd enneacontagon Number is = 267
Time Complexity: O(1)
Auxiliary Space: O(1)
Reference: https://en.wikipedia.org/wiki/Enneacontagon
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