Find the sum of the first Nth Heptadecagonal Number
Given a number N, the task is to find the sum of first N Heptadecagonal Numbers.
The first few heptadecagonal numbers are 1, 17, 48, 94, 155, 231 …
Examples:
Input: N = 3
Output: 66
Explanation:
1, 17 and 48 are the first three heptadecagonal numbers.
Input: N = 6
Output: 546
Approach:
- Initially, we need to create a function which will help us to calculate the Nth heptadecagonal number.
- Now, run a loop starting from 1 to N, to find ith heptadecagonal number.
- Add all the above calculated heptadecagonal numbers.
- Finally, display the sum of the first N heptadecagonal numbers.
Below is the implementation of the above approach:
C++
// C++ program to find the sum of the // first N heptadecagonal numbers #include <bits/stdc++.h> using namespace std; // Function to find the N-th // heptadecagonal number int heptadecagonal_num( int n) { // Formula to calculate nth // heptadecagonal number return ((15 * n * n) - 13 * n) / 2; } // Function to find the sum of the // first N heptadecagonal numbers int sum_heptadecagonal_num( int n) { // Variable to store the sum int summ = 0; // Iterating from 1 to N for ( int i = 1; i < n + 1; i++) { // Finding the sum summ += heptadecagonal_num(i); } return summ; } // Driver code int main() { int n = 5; cout << sum_heptadecagonal_num(n); } // This code is contributed by coder001 |
Java
// Java program to find the sum of the // first N heptadecagonal numbers class GFG{ // Function to find the N-th // heptadecagonal number public static int heptadecagonal_num( int n) { // Formula to calculate nth // heptadecagonal number return (( 15 * n * n) - 13 * n) / 2 ; } // Function to find the sum of the // first N heptadecagonal numbers public static int sum_heptadecagonal_num( int n) { // Variable to store the sum int summ = 0 ; // Iterating from 1 to N for ( int i = 1 ; i < n + 1 ; i++) { // Finding the sum summ += heptadecagonal_num(i); } return summ; } // Driver code public static void main(String[] args) { int n = 5 ; System.out.println(sum_heptadecagonal_num(n)); } } // This code is contributed by divyeshrabadiya07 |
Python3
# Python3 program to find the sum # of the first N # heptadecagonal numbers # Function to find the # N-th heptadecagonal # number def heptadecagonal_num(n): # Formula to calculate # nth heptadecagonal # number return (( 15 * n * n) - 13 * n) / / 2 # Function to find the # sum of the first N # heptadecagonal numbers def sum_heptadecagonal_num(n) : # Variable to store # the sum summ = 0 # Iterate from 1 to N for i in range ( 1 , n + 1 ): summ + = heptadecagonal_num(i) return summ # Driver code if __name__ = = '__main__' : n = 5 print (sum_heptadecagonal_num(n)) |
C#
// C# program to find the sum of the // first N heptadecagonal numbers using System; class GFG{ // Function to find the N-th // heptadecagonal number public static int heptadecagonal_num( int n) { // Formula to calculate nth // heptadecagonal number return ((15 * n * n) - 13 * n) / 2; } // Function to find the sum of the // first N heptadecagonal numbers public static int sum_heptadecagonal_num( int n) { // Variable to store the sum int summ = 0; // Iterating from 1 to N for ( int i = 1; i < n + 1; i++) { // Finding the sum summ += heptadecagonal_num(i); } return summ; } // Driver code public static void Main() { int n = 5; Console.WriteLine(sum_heptadecagonal_num(n)); } } // This code is contributed by Code_Mech |
Javascript
<script> // Javascript program to find the sum of the // first N heptadecagonal numbers // Function to find the N-th // heptadecagonal number function heptadecagonal_num(n) { // Formula to calculate nth // heptadecagonal number return ((15 * n * n) - 13 * n) / 2; } // Function to find the sum of the // first N heptadecagonal numbers function sum_heptadecagonal_num(n) { // Variable to store the sum let summ = 0; // Iterating from 1 to N for (let i = 1; i < n + 1; i++) { // Finding the sum summ += heptadecagonal_num(i); } return summ; } let n = 5; document.write(sum_heptadecagonal_num(n)); // This code is contributed by divyesh072019. </script> |
Output:
315
Time complexity: O(N).
Auxiliary space: O(1) since it is using constant space for variables