# Program to find Nth term of the series 3 , 5 , 21 , 51 , 95 , …

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

3, 5, 21, 51, 95, ….

**Examples:**

Input:N = 4Output:51Explanation:Nth term = (7 * pow(N, 2) - 19 * N + 15) = (7 * pow(4, 2) - 19 * 4 + 15) = 51Input:N = 10Output:525

**Approach:**

The Nth term of the given series can be generalized as:

[Tex] [/Tex]

Below is the implementation of the above approach:

## C++

`// CPP program to find N-th term of the series:` `// 3, 5, 21, 51, 95,...` `#include <iostream>` `#include <math.h>` `using` `namespace` `std;` `// calculate Nth term of series` `int` `getNthTerm(` `long` `long` `int` `N)` `{` ` ` `// Return Nth term` ` ` `return` `(7 * ` `pow` `(N, 2) - 19 * N + 15);` `}` `// driver code` `int` `main()` `{` ` ` `// declaration of number of terms` ` ` `long` `long` `int` `N = 4;` ` ` `// Get the Nth term` ` ` `cout << getNthTerm(N);` ` ` `return` `0;` `}` |

## Java

`// Java program to find N-th term of the series:` `// 3, 5, 21, 51, 95,...` `import` `java.util.*;` `class` `solution` `{` `static` `long` `getNthTerm(` `long` `N)` `{` `// Return Nth term` ` ` `return` `(` `7` `*(` `int` `) Math.pow(N, ` `2` `) - ` `19` `* N + ` `15` `);` `}` `//Driver program` `public` `static` `void` `main(String arr[])` `{` `// declaration of number of terms` ` ` `long` `N = ` `4` `;` ` ` `// Get the Nth term` ` ` `System.out.println(getNthTerm(N));` `}` `}` |

## Python3

`# Python3 program to find N-th term` `# of the series:` `# 3, 5, 21, 51, 95,...` `# calculate Nth term of series` `def` `getNthTerm(N):` ` ` ` ` `#Return Nth term` ` ` `return` `(` `7` `*` `pow` `(N, ` `2` `) ` `-` `19` `*` `N ` `+` `15` `)` ` ` `#Driver code` `if` `__name__` `=` `=` `'__main__'` `:` ` ` `#declaration of number of terms` ` ` `N ` `=` `4` `#Get the Nth term` ` ` `print` `(getNthTerm(N))` `#this code is contributed by Shashank_Sharma` |

## C#

`// C# program to find` `// N-th term of the series:` `// 3, 5, 21, 51, 95,...` `using` `System;` `class` `GFG` `{` `static` `long` `getNthTerm(` `long` `N)` `{` ` ` `// Return Nth term` ` ` `return` `(7 *(` `int` `) Math.Pow(N, 2) -` ` ` `19 * N + 15);` `}` `// Driver Code` `static` `public` `void` `Main ()` `{` ` ` `// declaration of number` ` ` `// of terms` ` ` `long` `N = 4;` ` ` `// Get the Nth term` ` ` `Console.Write(getNthTerm(N));` `}` `}` `// This code is contributed by Raj` |

## PHP

`<?php` `// PHP program to find` `// N-th term of the series:` `// 3, 5, 21, 51, 95,...` `// calculate Nth term of series` `function` `getNthTerm(` `$N` `)` `{` ` ` `// Return Nth term` ` ` `return` `(7 * pow(` `$N` `, 2) -` ` ` `19 * ` `$N` `+ 15);` `}` `// Driver code` `// declaration of number` `// of terms` `$N` `= 4;` `// Get the Nth term` `echo` `getNthTerm(` `$N` `);` `// This code is contributed` `// by anuj_67` `?>` |

## Javascript

`<script>` `// JavaScript program to find N-th term of the series:` `// 3, 5, 21, 51, 95,...` `// calculate Nth term of series` `function` `getNthTerm(N)` `{` ` ` `// Return Nth term` ` ` `return` `(7 * Math.pow(N, 2) - 19 * N + 15);` `}` `// driver code` ` ` `// declaration of number of terms` ` ` `let N = 4;` ` ` `document.write( getNthTerm(N) );` `// This code contributed by gauravrajput1` `</script>` |

**Output:**

51

**Time Complexity:** O(1)

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