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 NthDodecagonal 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)
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