# Second hexagonal numbers

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

3, 10, 21, 36, 55, 78, 105, 136, 171, 210, 253, …..

Nth term

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

Input:N = 1Output:3Input:N = 4Output:36

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

1st Term = 1 * (2*1 + 1) = 3

2nd term = 2 * (2*2 + 1) = 10

3rd term = 3 * (2*3 + 1) = 21

4th term = 4 * (2*4 + 1) = 36

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.

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Nth term = n * (2*n + 1)

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 * (2 * n + 1) << endl;` `}` `// Driver code` `int` `main()` `{` ` ` `int` `N = 4;` ` ` `findNthTerm(N);` ` ` `return` `0;` `}` |

## Java

`// Java implementation to` `// find N-th term` `// in the series` `class` `GFG{` ` ` `// Function to find N-th term` `// in the series` `static` `void` `findNthTerm(` `int` `n)` `{` ` ` `System.out.print(n * (` `2` `* n + ` `1` `));` `}` `// Driver code` `public` `static` `void` `main (String[] args)` `{` ` ` `int` `N = ` `4` `;` ` ` `findNthTerm(N);` `}` `}` `// This code is contributed by Ritik Bansal` |

## 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 ` `*` `(` `2` `*` `n ` `+` `1` `))` `# Driver code` `N ` `=` `4` `# Function call` `findNthTerm(N)` `# This code is contributed by Vishal Maurya` |

## C#

`// C# implementation to` `// find N-th term` `// in the series` `using` `System;` `class` `GFG{` ` ` `// Function to find N-th term` `// in the series` `static` `void` `findNthTerm(` `int` `n)` `{` ` ` `Console.Write(n * (2 * n + 1));` `}` `// Driver code` `public` `static` `void` `Main()` `{` ` ` `int` `N = 4;` ` ` `findNthTerm(N);` `}` `}` `// This code is contributed by Code_Mech` |

## 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 * (2 * n + 1));` `}` `// Driver code` `N = 4;` `findNthTerm(N);` `</script>` |

**Output:**

36

**Time Complexity:** O(1)**Auxiliary Space:** O(1)

**Reference:**OEIS

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