Find the sum of the first N Centered Octadecagonal Numbers
Given a number N, the task is to find the sum of first N Centered Octadecagonal numbers.
Examples:
Input: N = 3
Output: 75
Explanation:
1, 19 and 55 are the first three centered octadecagonal numbers.
Input: N = 10
Output: 298
Approach:
- Initially, we need to create a function which will help us to calculate the Nth centered octadecagonal number.
- Now, run a loop starting from 1 to N, to find ith centered octadecagonal numbers.
- Add all the above calculated centered octadecagonal numbers.
- Finally, display the sum of the first N centered octadecagonal numbers.
Below is the implementation of the above approach:
C++
// C++ program to find the sum of the // first N centered octadecagonal numbers #include<bits/stdc++.h> using namespace std; // Function to find the N-th centered // octadecagonal number int center_octadecagon_num( int n) { // Formula to calculate // nth centered octadecagonal // number return (9 * n * n - 9 * n + 1); } // Function to find the sum of the first // N centered octadecagonal numbers int sum_center_octadecagon_num( int n) { // Variable to store // the sum int summ = 0; // Iterating through the range // 1 to N for ( int i = 1; i < n + 1; i++) { summ += center_octadecagon_num(i); } return summ; } // Driver Code int main() { int n = 3; cout << (sum_center_octadecagon_num(n)); return 0; } // This code is contributed by Rajput-Ji |
Java
// Java program to find the sum of the // first N centered octadecagonal numbers class GFG { // Function to find the N-th centered // octadecagonal number static int center_octadecagon_num( int n) { // Formula to calculate // nth centered octadecagonal // number return ( 9 * n * n - 9 * n + 1 ); } // Function to find the sum of the first // N centered octadecagonal numbers static int sum_center_octadecagon_num( int n) { // Variable to store // the sum int summ = 0 ; // Iterating through the range // 1 to N for ( int i = 1 ; i < n + 1 ; i++) { summ += center_octadecagon_num(i); } return summ; } // Driver Code public static void main(String[] args) { int n = 3 ; System.out.println(sum_center_octadecagon_num(n)); } } // This code is contributed by sapnasingh4991 |
Python3
# Python3 program to find the sum of # the first N Centered Octadecagonal # numbers # Function to find the N-th # Centered octadecagonal # number def center_octadecagon_num(n): # Formula to calculate # nth centered octadecagonal # number return ( 9 * n * n - 9 * n + 1 ) # Function to find the sum of # the first N Centered # octadecagonal numbers def sum_center_octadecagon_num(n) : # Variable to store # the sum summ = 0 # Iterating through the range # 1 to N for i in range ( 1 , n + 1 ): summ + = center_octadecagon_num(i) return summ # Driver code if __name__ = = '__main__' : n = 3 print (sum_center_octadecagon_num(n)) |
C#
// C# program to find the sum of the // first N centered octadecagonal numbers using System; class GFG { // Function to find the N-th centered // octadecagonal number static int center_octadecagon_num( int n) { // Formula to calculate // nth centered octadecagonal // number return (9 * n * n - 9 * n + 1); } // Function to find the sum of the first // N centered octadecagonal numbers static int sum_center_octadecagon_num( int n) { // Variable to store // the sum int summ = 0; // Iterating through the range // 1 to N for ( int i = 1; i < n + 1; i++) { summ += center_octadecagon_num(i); } return summ; } // Driver Code public static void Main(String[] args) { int n = 3; Console.WriteLine(sum_center_octadecagon_num(n)); } } // This code is contributed by sapnasingh4991 |
Javascript
<script> // Javascript program to find the sum of the // first N centered octadecagonal numbers // Function to find the N-th centered // octadecagonal number function center_octadecagon_num(n) { // Formula to calculate // nth centered octadecagonal // number return (9 * n * n - 9 * n + 1); } // Function to find the sum of the first // N centered octadecagonal numbers function sum_center_octadecagon_num(n) { // Variable to store // the sum let summ = 0; // Iterating through the range // 1 to N for (let i = 1; i < n + 1; i++) { summ += center_octadecagon_num(i); } return summ; } let n = 3; document.write(sum_center_octadecagon_num(n)); // This code is contributed by divyeshrabadiya07. </script> |
Output:
75
Time Complexity: O(N).
Auxiliary Space: O(1) since constant variables are being used
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