The **Second decagonal numbers** series can be represented as

7, 22, 45, 76, 115, 162, 217, 280,,…..

Nth term

Given an integer **N**. The task is to find the N-th term of the given series.**Examples**:

Input:N = 1Output:7

Input:N = 4Output:76

**Approach:** The idea is to find the general term for the Second decagonal numbers. Below is the computation of the general term for second decagonal numbers:

1st Term = 1 * (4*1 + 3) = 7

2nd term = 2 * (4*2 + 3) = 22

3rd term = 3 * (4*3 + 3) = 45

4th term = 4 * (4*4 + 3) = 76

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Nth term = n * (4 * n + 3)

Therefore, the Nth term of the series is given as

Below is the implementation of above approach:

## C++

`// C++ implementation to` `// find N-th term in the series` `#include <iostream>` `#include <math.h>` `using` `namespace` `std;` `// Function to find N-th term` `// in the series` `void` `findNthTerm(` `int` `n)` `{` ` ` `cout << n * (4 * n + 3) << endl;` `}` `// Driver Code` `int` `main()` `{` ` ` `int` `N = 4;` ` ` `findNthTerm(N);` ` ` `return` `0;` `}` |

## Java

`// Java program for the above approach` `class` `GFG{` `// Function to find N-th term` `// in the series` `static` `void` `findNthTerm(` `int` `n)` `{` ` ` `System.out.println(n * (` `4` `* n + ` `3` `));` `}` `// Driver code` `public` `static` `void` `main(String[] args)` `{` ` ` `int` `N = ` `4` `;` ` ` ` ` `findNthTerm(N);` `}` `}` `// This code is contributed by Pratima Pandey` |

## Python3

`# Python3 implementation to` `# find N-th term in the series` `# Function to find N-th term` `# in the series` `def` `findNthTerm(n):` ` ` `print` `(n ` `*` `(` `4` `*` `n ` `+` `3` `))` `# Driver Code` `N ` `=` `4` `;` `findNthTerm(N);` `# This code is contributed by Code_Mech` |

## C#

`// C# program for the above approach` `using` `System;` `class` `GFG{` `// Function to find N-th term` `// in the series` `static` `void` `findNthTerm(` `int` `n)` `{` ` ` `Console.WriteLine(n * (4 * n + 3));` `}` `// Driver code` `public` `static` `void` `Main(String[] args)` `{` ` ` `int` `N = 4;` ` ` ` ` `findNthTerm(N);` `}` `}` `// This code is contributed by 29AjayKumar` |

## Javascript

`<script>` `// Javascript implementation to` `// find N-th term in the series` `// Function to find N-th term` `// in the series` `function` `findNthTerm(n)` `{` ` ` `document.write(n * (4 * n + 3));` `}` `// Driver Code` `let N = 4;` `findNthTerm(N);` `// This code is contributed by subhammahato348.` `</script>` |

**Output:**

76

**Time Complexity:** O(1)

**Auxiliary Space:** O(1)

**Reference:** OEIS

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