# Find N-th term of series 2, 8, 18, 32, 50…

• Last Updated : 11 Feb, 2022

Given the series 2, 8, 18, 32, 50…, find the Nth term of the series.

Examples:

Input: N = 1
Output: 2

Input: N = 3
Output: 18

Input: N = 5
Output: 50

Approach:

For finding the nth term we need to find the relation between n and each term.

1st term = 2 =  2*(12) // 2*first perfect square

2nd term = 8 = 2*(22) // 2*second perfect square

3rd term = 18 = 2*(32) //  2*third perfect square

4th term = 32 = 2*(42) //  2*fourth perfect square

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Nth term = 2*(Nth perfect square)

Formula-

TN = 2 * N ^ 2

Illustration-

Input: N = 5
Output: 50
Explanation-
TN = 2 * N ^ 2
= 2* 5 ^ 2
= 2 * 25
= 50

Below is the C++ program to implement the above approach-

## C++

 `// C++ program to implement``// the above approach``#include ``using` `namespace` `std;` `// Find n-th term of series``// 2, 8, 18, 32, 50...``int` `nthTerm(``int` `N)``{` `    ``// Nth perfect square is N * N``    ``int` `Nthperfectsquare = N * N;` `    ``return` `2 * Nthperfectsquare;``}``// Driver code``int` `main()``{``    ``int` `N = 5;` `    ``cout << nthTerm(N) << endl;``    ``return` `0;``}`

## Java

 `// Java code for the above approach` `import` `java.io.*;` `class` `GFG {``  ` `// Find n-th term of series``// 2, 8, 18, 32, 50...``static` `int` `nthTerm(``int` `N)``{` `    ``// Nth perfect square is N * N``    ``int` `Nthperfectsquare = N * N;` `    ``return` `2` `* Nthperfectsquare;``}``// Driver code``    ``public` `static` `void` `main (String[] args) {``      ` `       ``int` `N = ``5``;` `        ``System.out.println(nthTerm(N));``    ``}``}``// This code is contributed by Potta Lokesh`

## Python

 `# Python program to implement``# the above approach` `# Find n-th term of series``# 2, 8, 18, 32, 50...``def` `nthTerm(N):` `    ``# Nth perfect square is N * N``    ``Nthperfectsquare ``=` `N ``*` `N` `    ``return` `2` `*` `Nthperfectsquare` `# Driver Code``if` `__name__ ``=``=` `"__main__"``:``  ` `    ``N ``=` `5``    ` `    ``print``(nthTerm(N))` `# This code is contributed by Samim Hossain Mondal.`

## C#

 `using` `System;` `public` `class` `GFG{` `// Find n-th term of series``// 2, 8, 18, 32, 50...``static` `int` `nthTerm(``int` `N)``{` `    ``// Nth perfect square is N * N``    ``int` `Nthperfectsquare = N * N;` `    ``return` `2 * Nthperfectsquare;``}` `// Driver code``static` `public` `void` `Main (){` `    ``int` `N = 5;``    ``Console.Write(nthTerm(N));``}``}` `// This code is contributed by hrithikgarg03188`

## Javascript

 ``

Output:
`50`

Time Complexity: O(1)
Auxiliary Space: O(1)

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