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# Find N-th term in the series 0, 4, 18, 48, 100 …

Given a series 0, 4, 18, 48, 100 . . .  and an integer N, the task is to find the N-th term of the series.

Examples:

Input: N = 4
Output: 48
Explanation: As given in the sequence we can see that 4th term is 48

Input: N = 6
Output: 180

Approach: Consider the below observation:

For N = 2, the 2nd term is 4, which can be represented as 8 – 4, i.e. 23 – 22

For N = 3, the 3rd term is 18, which can be represented as 27 – 9, i.e. 33 – 32

For N = 4, the 4th term is 18, which can be represented as 27 – 9, i.e. 43 – 42

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.

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Similarly, The N-th term of this series can be represented as N3 – N2

So for any N, find the square of that N and subtract it from the cube of the number.

Below is the implementation of the above approach:

## C++

 `// C++ code to find Nth term of series``// 0, 4, 18, ...`` ` `#include ``using` `namespace` `std;`` ` `// Function to find N-th term``// of the series``int` `getNthTerm(``int` `N)``{``    ``// (pow(N, 3) - pow(N, 2))``    ``return` `(N * N * N) - (N * N);``}`` ` `// Driver Code``int` `main()``{``    ``int` `N = 4;`` ` `    ``// Get the 8th term of the series``    ``cout << getNthTerm(N);``    ``return` `0;``}`

## Java

 `// Java code to find Nth term of series``// 0, 4, 18, ...``class` `GFG``{``   ` `    ``// Function to find N-th term``    ``// of the series``    ``public` `static` `int` `getNthTerm(``int` `N) ``    ``{``       ` `        ``// (pow(N, 3) - pow(N, 2))``        ``return` `(N * N * N) - (N * N);``    ``}`` ` `    ``// Driver Code``    ``public` `static` `void` `main(String args[])``    ``{``        ``int` `N = ``4``;`` ` `        ``// Get the 8th term of the series``        ``System.out.println(getNthTerm(N));``    ``}``}`` ` `// This code is contributed by gfgking`

## Python3

 `# Python code to find Nth term of series``# 0, 4, 18, ...`` ` `# Function to find N-th term``# of the series``def` `getNthTerm(N):``   ` `    ``# (pow(N, 3) - pow(N, 2))``    ``return` `(N ``*` `N ``*` `N) ``-` `(N ``*` `N);`` ` `# Driver Code``N ``=` `4``;`` ` `# Get the 8th term of the series``print``(getNthTerm(N));`` ` `# This code is contributed by gfgking`

## C#

 `// C# code to find Nth term of series``// 0, 4, 18, ...`` ` `using` `System;``class` `GFG {``    ``// Function to find N-th term``    ``// of the series``    ``public` `static` `int` `getNthTerm(``int` `N) {``        ``// (pow(N, 3) - pow(N, 2))``        ``return` `(N * N * N) - (N * N);``    ``}`` ` `    ``// Driver Code``    ``public` `static` `void` `Main() {``        ``int` `N = 4;`` ` `        ``// Get the 8th term of the series``        ``Console.Write(getNthTerm(N));``    ``}``}`` ` `// This code is contributed by gfgking`

## Javascript

 ``

Output

`48`

Time complexity: O(1)
Auxiliary space: O(1)

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