Icositrigonal Number
Given a number N, the task is to find Nth Icositrigonal number or not.
An Icositrigonal number is class of figurate number. It has 23 – sided polygon called Icositrigon. The N-th Icositrigonal number count’s the 23 number of dots and all others dots are surrounding with a common sharing corner and make a pattern. The first few Icositrigonol numbers are 1, 23, 66, 130, 215, 321, 448 …
Examples:
Input: N = 2
Output: 23
Explanation:
The second Icositrigonol number is 66.
Input: N = 6
Output: 321
Approach: The N-th Icositrigonal number is given by the formula:
Below is the implementation of the above approach:
C++
// C++ program to find nth // Icositrigonal number #include <bits/stdc++.h> using namespace std; // Function to find N-th // Icositrigonal number int Icositrigonal_num( int n) { // Formula to calculate nth // Icositrigonal number return (21 * n * n - 19 * n) / 2; } // Driver Code int main() { int n = 3; cout << Icositrigonal_num(n) << endl; n = 10; cout << Icositrigonal_num(n); return 0; } |
Java
// Java program to find nth // Icositrigonal number class GFG{ // Function to find N-th // Icositrigonal number static int IcositrigonalNum( int n) { // Formula to calculate nth // Icositrigonal number return ( 21 * n * n - 19 * n) / 2 ; } // Driver code public static void main(String[] args) { int n = 3 ; System.out.print(IcositrigonalNum(n) + "\n" ); n = 10 ; System.out.print(IcositrigonalNum(n)); } } // This code is contributed by spp____ |
Python3
# Python3 program to find nth # Icositrigonal number # Function to find N-th # Icositrigonal number def IcositrigonalNum(n): # Formula to calculate nth # Icositrigonal number return ( 21 * n * n - 19 * n) / 2 ; # Driver code n = 3 print (IcositrigonalNum(n)) n = 10 print (IcositrigonalNum(n)) # This code is contributed by spp____ |
C#
// C# program to find nth // Icositrigonal number using System; class GFG{ // Function to find N-th // Icositrigonal number static int IcositrigonalNum( int n) { // Formula to calculate nth // Icositrigonal number return (21 * n * n - 19 * n) / 2; } // Driver code public static void Main() { int n = 3; Console.WriteLine(IcositrigonalNum(n)); n = 10; Console.WriteLine(IcositrigonalNum(n)); } } // This code is contributed by spp____ |
Javascript
<script> // Javascript program to find nth // Icositrigonal number // Function to find N-th // Icositrigonal number function Icositrigonal_num(n) { // Formula to calculate nth // Icositrigonal number return (21 * n * n - 19 * n) / 2; } let n = 3; document.write(Icositrigonal_num(n) + "</br>" ); n = 10; document.write(Icositrigonal_num(n)); </script> |
Output:
66 955
Reference: https://en.wikipedia.org/wiki/Polygonal_number