Given a positive integer N, the task is to find the Nth term of the series
0, 6, 24, 60, 120…till N terms
Examples:
Input: N = 5
Output: 120Input: N = 10
Output: 990
Approach:
From the given series, find the formula for Nth term-
1st term = 1 ^ 3 – 1 = 0
2nd term = 2 ^ 3 – 2 = 6
3rd term = 3 ^ 3 – 3 = 24
4th term = 4 ^ 3 – 4 = 60
.
.
Nth term = N ^ 3 – N
The Nth term of the given series can be generalized as-
TN = N ^ 3 – N
Illustration:
Input: N = 10
Output: 990
Explanation:
TN = N ^ 3 – N
= 10 ^ 3 – 10
= 1000 – 10
= 990
Below is the implementation of the above approach-
// C++ program to implement // the above approach #include <iostream> using namespace std;
// Function to return // Nth term of the series int nth( int n)
{ return n * n * n - n;
} // Driver code int main()
{ int N = 5;
cout << nth(N) << endl;
return 0;
} |
// C program to implement // the above approach #include <stdio.h> // Function to return // Nth term of the series int nth( int n)
{ return n * n * n - n;
} // Driver code int main()
{ // Value of N
int N = 5;
printf ( "%d" , nth(N));
return 0;
} |
// Java program to implement // the above approach import java.io.*;
class GFG {
// Driver code
public static void main(String[] args)
{
int N = 5 ;
System.out.println(nth(N));
}
// Function to return
// Nth term of the series
public static int nth( int n)
{
return n * n * n - n;
}
} |
# Python program to implement # the above approach # Function to return # Nth term of the series def nth(n):
return n * n * n - n
# Driver code N = 5
print (nth(N))
# This code is contributed by Samim Hossain Mondal. |
using System;
public class GFG
{ // Function to return
// Nth term of the series
public static int nth( int n) { return n * n * n - n; }
// Driver code
static public void Main()
{
// Code
int N = 5;
Console.Write(nth(N));
}
} // This code is contributed by Potta Lokesh |
<script> // JavaScript code for the above approach
// Function to return
// Nth term of the series
function nth(n)
{
return n * n * n - n;
}
// Driver code
let N = 5;
document.write(nth(N) + '<br>' );
// This code is contributed by Potta Lokesh
</script>
|
120
Time Complexity: O(1) // since no loop is used the algorithm takes up constant time to perform the operations
Auxiliary Space: O(1) // since no extra array is used so the space taken by the algorithm is constant