# Find Nth term of the series 5, 13, 25, 41, 61…

Given a number N. The task is to write a program to find the Nth term in the below series:

5, 13, 25, 41, 61...

**Examples:**

Input :3Output :25 For N = 3 Nth term = 3*3 + (3+1)*(3+1) = 25Input :5Output :61

On observing carefully, the Nth term of the given series can be generalised as:

Nth term = N^{2}+ (N+1)^{2}

Below is the implementation of the above approach:

## C++

`// CPP program to find N-th term of the series:` `// 5, 13, 25, 41, 61...` `#include <iostream>` `using` `namespace` `std;` `// calculate Nth term of series` `int` `nthTerm(` `int` `N)` `{` ` ` `return` `N * N + (N + 1) * (N + 1);` `}` `// Driver Function` `int` `main()` `{` ` ` `int` `N = 3;` ` ` `cout << nthTerm(N);` ` ` `return` `0;` `}` |

## Java

`// Java program to calculate Nth term of` `// the series: 5, 13, 25, 41, 61...` `import` `java.io.*;` `class` `Nth {` ` ` `public` `static` `int` `nthTerm(` `int` `N)` ` ` `{` ` ` `// By using above formula` ` ` `return` `N * N + (N + ` `1` `) * (N + ` `1` `);` ` ` `}` ` ` ` ` `public` `static` `void` `main(String[] args)` ` ` `{` ` ` `int` `N = ` `3` `; ` `// Nth term is 25` ` ` ` ` `// call and print Nth term` ` ` `System.out.println(nthTerm(N));` ` ` `} ` `}` |

## Python 3

`# Python 3 program to find` `# N-th term of the series:` `# 5, 13, 25, 41, 61...` `# Function to calculate` `# Nth term of series` `def` `nthTerm(N) :` ` ` `return` `N ` `*` `N ` `+` `(N ` `+` `1` `) ` `*` `(N ` `+` `1` `)` `# Driver Code` `if` `__name__ ` `=` `=` `"__main__"` `:` ` ` `N ` `=` `3` ` ` `# function calling` ` ` `print` `(nthTerm(N))` `# This code is contributed` `# by ANKITRAI1` |

## C#

`// C# program to calculate Nth term of` `// the series: 5, 13, 25, 41, 61...` `using` `System;` `class` `GFG` `{` `public` `static` `int` `nthTerm(` `int` `N)` `{` ` ` `// By using above formula` ` ` `return` `N * N + (N + 1) * (N + 1);` `}` `// Driver Code` `public` `static` `void` `Main()` `{` ` ` `int` `N = 3; ` `// Nth term is 25` ` ` ` ` `// call and print Nth term` ` ` `Console.Write(nthTerm(N));` `}` `}` `// This code is contributed` `// by ChitraNayal` |

## PHP

`<?php` `// PHP program to find N-th` `// term of the series:` `// 5, 13, 25, 41, 61...` `// calculate Nth term of series` `function` `nthTerm(` `$N` `)` `{` ` ` `return` `$N` `* ` `$N` `+ (` `$N` `+ 1) *` ` ` `(` `$N` `+ 1);` `}` `// Driver Code` `$N` `= 3;` `echo` `nthTerm(` `$N` `);` `// This code is contributed` `// by ChitraNayal` `?>` |

## Javascript

`<script>` `// JavaScript program to find N-th term of the series:` `// 5, 13, 25, 41, 61...` `// calculate Nth term of series` `function` `nthTerm( N)` `{` ` ` `return` `N * N + (N + 1) * (N + 1);` `}` `// Driver Function` ` ` `let N = 3;` ` ` `document.write(nthTerm(N));` ` ` `// This code contributed by Rajput-Ji` `</script>` |

**Output:**

25

**Time Complexity:** O(1)

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