Find the sum of the first N Dodecagonal Numbers
Given a number N the task is to find the sum of first N Dodecagonal Number.
The first few dodecagonal numbers are 1, 12, 33, 64, 105, 156, 217 …
Examples:
Input: N = 3
Output: 46
Explanation:
1, 12 and 33 are the first three Dodecagonal numbersInput: N = 5
Output: 215
Approach:
- Initially, we need to create a function that will help us to calculate the Nth Dodecagonal number.
- Run a loop starting from 1 to N, to find ith Dodecagonal number.
- Add all the above calculated Dodecagonal numbers.
- Finally, display the sum of the first N Dodecagonal numbers.
Below is the implementation of the above approach:
C++
// C++ program to find the sum of // the first N dodecagonal numbers #include <bits/stdc++.h> using namespace std; // Function to find the N-th // dodecagonal number int Dodecagonal_num( int n) { // Formula to calculate N-th // dodecagonal number return (5 * n * n - 4 * n); } // Function to find the sum of // the first N dodecagonal numbers int sum_Dodecagonal_num( int n) { // Variable to get the sum int summ = 0; // Iterating through the // first N numbers for ( int i = 1; i < n + 1; i++) { // Compute the sum summ += Dodecagonal_num(i); } return summ; } // Driver Code int main() { int n = 5; // Display first Nth // centered_decagonal number cout << (sum_Dodecagonal_num(n)); return 0; } // This code is contributed by PrinciRaj1992 |
Java
// Java program to find the sum of // the first N dodecagonal numbers class GFG { // Function to find the N-th // dodecagonal number static int Dodecagonal_num( int n) { // Formula to calculate N-th // dodecagonal number return ( 5 * n * n - 4 * n); } // Function to find the sum of // the first N dodecagonal numbers static int sum_Dodecagonal_num( int n) { // Variable to get the sum int summ = 0 ; // Iterating through the // first N numbers for ( int i = 1 ; i < n + 1 ; i++) { // Compute the sum summ += Dodecagonal_num(i); } return summ; } // Driver Code public static void main(String[] args) { int n = 5 ; // Display first Nth // centered_decagonal number System.out.println(sum_Dodecagonal_num(n)); } } // This code is contributed by sapnasingh4991 |
Python3
# Python3 program to find the # sum of the first N # Dodecagonal numbers # Function to find the N-th # Dodecagonal number def Dodecagonal_num(n): # Formula to calculate # N-th Dodecagonal # number return ( 5 * n * n - 4 * n) # Function to find the # sum of the first N # Dodecagonal numbers def sum_Dodecagonal_num(n) : # Variable to get the sum summ = 0 # Iterating through the # first N numbers for i in range ( 1 , n + 1 ): # Compute the sum summ + = Dodecagonal_num(i) return summ # Driver Code if __name__ = = '__main__' : n = 5 print (sum_Dodecagonal_num(n)) |
C#
// C# program to find the sum of // the first N dodecagonal numbers using System; class GFG { // Function to find the N-th // dodecagonal number static int Dodecagonal_num( int n) { // Formula to calculate N-th // dodecagonal number return (5 * n * n - 4 * n); } // Function to find the sum of // the first N dodecagonal numbers static int sum_Dodecagonal_num( int n) { // Variable to get the sum int summ = 0; // Iterating through the // first N numbers for ( int i = 1; i < n + 1; i++) { // Compute the sum summ += Dodecagonal_num(i); } return summ; } // Driver Code public static void Main(String[] args) { int n = 5; // Display first Nth // centered_decagonal number Console.WriteLine(sum_Dodecagonal_num(n)); } } // This code is contributed by sapnasingh4991 |
Javascript
<script> // Javascript program to find the sum of // the first N dodecagonal numbers // Function to find the N-th // dodecagonal number function Dodecagonal_num(n) { // Formula to calculate N-th // dodecagonal number return (5 * n * n - 4 * n); } // Function to find the sum of // the first N dodecagonal numbers function sum_Dodecagonal_num(n) { // Variable to get the sum let summ = 0; // Iterating through the // first N numbers for (let i = 1; i < n + 1; i++) { // Compute the sum summ += Dodecagonal_num(i); } return summ; } let n = 5; // Display first Nth // centered_decagonal number document.write(sum_Dodecagonal_num(n)); </script> |
Output
215
Time Complexity: O(N).
Auxiliary Space: O(1)