# Program to print the series 1, 9, 17, 33, 49, 73, 97… till N terms

Given a number N, the task is to print the first N terms of the series: Examples:

Input: N = 7
Output: 1, 9, 17, 33, 49, 73, 97

Input: N = 3
Output: 1, 9, 17

## Recommended: Please try your approach on {IDE} first, before moving on to the solution.

Approach: From the given series, find the formula for Nth term:

```1st term = 1
2nd term = 9 = 2 * 4 + 1
3rd term = 17 = 2 * 9 - 1
4th term = 33 = 2 * 16 + 1
5th term = 49 = 2 * 25 - 1
6th term = 73 = 2 * 36 + 1
.
.
Nth term = (2 * N2 + (-1)N)
```

Therefore:

Nth term of the series Then iterate over numbers in the range [1, N] to find all the terms using the above formula and print them.

Below is the implementation of the above approach:

## CPP

 `// C++ implementation of the above approach ` ` `  `#include "bits/stdc++.h" ` `using` `namespace` `std; ` ` `  `// Function to print the series ` `void` `printSeries(``int` `N) ` `{ ` ` `  `    ``int` `ith_term = 0; ` ` `  `    ``// Generate the ith term and ` `    ``// print it ` `    ``for` `(``int` `i = 1; i <= N; i++) { ` ` `  `        ``ith_term = i % 2 == 0 ` `                       ``? 2 * i * i + 1 ` `                       ``: 2 * i * i - 1; ` `        ``cout << ith_term << ``", "``; ` `    ``} ` `} ` ` `  `// Driver Code ` `int` `main() ` `{ ` `    ``int` `N = 7; ` ` `  `    ``printSeries(N); ` `    ``return` `0; ` `} `

## Java

 `// Java implementation of the above approach ` `import` `java.util.*; ` ` `  `class` `GFG{ ` `  `  `// Function to print the series ` `static` `void` `printSeries(``int` `N) ` `{ ` `  `  `    ``int` `ith_term = ``0``; ` `  `  `    ``// Generate the ith term and ` `    ``// print it ` `    ``for` `(``int` `i = ``1``; i <= N; i++) { ` `  `  `        ``ith_term = i % ``2` `== ``0` `                       ``? ``2` `* i * i + ``1` `                       ``: ``2` `* i * i - ``1``; ` `        ``System.out.print(ith_term+ ``", "``); ` `    ``} ` `} ` `  `  `// Driver Code ` `public` `static` `void` `main(String[] args) ` `{ ` `    ``int` `N = ``7``; ` `  `  `    ``printSeries(N); ` `} ` `} ` ` `  `// This code is contributed by PrinciRaj1992 `

## Python3

 `# Python implementation of the above approach ` ` `  `# Function to prthe series ` `def` `printSeries(N): ` ` `  `    ``ith_term ``=` `0``; ` ` `  `    ``# Generate the ith term and ` `    ``# prit ` `    ``for` `i ``in` `range``(``1``,N``+``1``): ` ` `  `        ``ith_term ``=` `0``; ` `        ``if``(i ``%` `2` `=``=` `0``): ` `            ``ith_term ``=` `2` `*` `i ``*` `i ``+` `1``; ` `        ``else``: ` `            ``ith_term ``=` `2` `*` `i ``*` `i ``-` `1``; ` `        ``print``(ith_term,end``=` `", "``); ` `     `  `# Driver Code ` `if` `__name__ ``=``=` `'__main__'``: ` `    ``N ``=` `7``; ` ` `  `    ``printSeries(N); ` `     `  `# This code is contributed by Princi Singh `

## C#

 `// C# implementation of the above approach ` `using` `System; ` ` `  `class` `GFG{ ` ` `  `// Function to print the series ` `static` `void` `printSeries(``int` `N) ` `{ ` ` `  `    ``int` `ith_term = 0; ` ` `  `    ``// Generate the ith term and ` `    ``// print it ` `    ``for` `(``int` `i = 1; i <= N; i++) { ` ` `  `        ``ith_term = i % 2 == 0? 2 * i * i + 1:  ` `                                ``2 * i * i - 1; ` `        ``Console.Write(ith_term+ ``", "``); ` `    ``} ` `} ` ` `  `// Driver Code ` `public` `static` `void` `Main() ` `{ ` `    ``int` `N = 7; ` ` `  `    ``printSeries(N); ` `} ` `} ` ` `  `// This code is contributed by AbhiThakur `

Output:

```1, 9, 17, 33, 49, 73, 97,
```

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