Program to find the Nth term of the series 3, 7, 13, 21, 31…..

Given a number N, the task is to find the Nth term of this series:

3, 7, 13, 21, 31, …….

**Examples:**

Input:N = 4Output:21Explanation:Nth term = (pow(N, 2) + N + 1) = (pow(4, 2) + 4 + 1) = 21Input:N = 11Output:133

**Approach:**

Subtracting these two equations we get

Therefore, the Nth Term of the given series is:

Below is the implementation of the above approach:

## C++

`// CPP program to find the Nth term of given series. ` `#include <iostream> ` `#include <math.h> ` `using` `namespace` `std; ` ` ` `// Function to calculate sum ` `long` `long` `int` `getNthTerm(` `long` `long` `int` `N) ` `{ ` ` ` `// Return Nth term ` ` ` `return` `(` `pow` `(N, 2) + N + 1); ` `} ` ` ` `// driver code ` `int` `main() ` `{ ` ` ` `// declaration of number of terms ` ` ` `long` `long` `int` `N = 11; ` ` ` ` ` `// Get the Nth term ` ` ` `cout << getNthTerm(N); ` ` ` ` ` `return` `0; ` `} ` |

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## Java

`// Java code to find the Nth term of given series. ` `import` `java.util.*; ` ` ` `class` `solution ` `{ ` ` ` `// Function to calculate sum ` `static` `long` `getNthTerm(` `long` `N) ` `{ ` ` ` ` ` `// Return Nth term ` ` ` `return` `((` `int` `)Math.pow(N, ` `2` `) + N + ` `1` `); ` `} ` ` ` `//Driver program ` `public` `static` `void` `main(String arr[]) ` `{ ` ` ` ` ` `// declaration of number of terms ` ` ` `long` `N = ` `11` `; ` ` ` ` ` `// Get the Nth term ` ` ` `System.out.println(getNthTerm(N)); ` ` ` `} ` `} ` `//THis code is contibuted by ` `//Surendra_Gangwar ` |

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## Python3

`# Python3 Code to find the ` `# Nth term of given series. ` ` ` `# Function to calculate sum ` `def` `getNthTerm(N): ` ` ` ` ` `# Return Nth term ` ` ` `return` `(` `pow` `(N, ` `2` `) ` `+` `N ` `+` `1` `) ` ` ` `# driver code ` `if` `__name__` `=` `=` `'__main__'` `: ` ` ` `# declaration of number of terms ` ` ` `N ` `=` `11` ` ` `# Get the Nth term ` ` ` `print` `(getNthTerm(N)) ` ` ` `# This code is contributed by ` `# Sanjit_Prasad ` |

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## C#

`// C# code to find the Nth ` `// term of given series. ` `using` `System; ` ` ` `class` `GFG ` `{ ` ` ` `// Function to calculate sum ` `static` `long` `getNthTerm(` `long` `N) ` `{ ` ` ` `// Return Nth term ` ` ` `return` `((` `int` `)Math.Pow(N, 2) + N + 1); ` `} ` ` ` `// Driver Code ` `static` `public` `void` `Main () ` `{ ` ` ` ` ` `// declaration of number ` ` ` `// of terms ` ` ` `long` `N = 11; ` ` ` ` ` `// Get the Nth term ` ` ` `Console.Write(getNthTerm(N)); ` `} ` `} ` ` ` `// This code is contibuted by Raj ` |

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## PHP

`<?php ` `// PHP program to find the ` `// Nth term of given series ` ` ` `// Function to calculate sum ` `function` `getNthTerm(` `$N` `) ` `{ ` ` ` `// Return Nth term ` ` ` `return` `(pow(` `$N` `, 2) + ` `$N` `+ 1); ` `} ` ` ` `// Driver code ` ` ` `// declaration of number of terms ` `$N` `= 11; ` ` ` `// Get the Nth term ` `echo` `getNthTerm(` `$N` `); ` ` ` `// This code is contributed by Raj ` `?> ` |

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**Output:**

133

**Time Complexity:** O(1)

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