# C#: Get the nth tetrahedral number from a given integer(n) value

## C# Sharp Math: Exercise-21 with Solution

Write a C# Sharp program to get the nth tetrahedral number from a given integer(n) value.

A tetrahedral number, or triangular pyramidal number, is a figurate number that represents a pyramid with a triangular base and three sides, called a tetrahedron. The formula for the nth tetrahedral number is represented by the 3rd rising factorial of n divided by the factorial of 3:

Example of tetrahedral numbers:

N | Tetrahedral Number |
---|---|

1 | 1 |

2 | 4 |

3 | 10 |

4 | 20 |

5 | 35 |

6 | 56 |

**Sample Solution:**

**C# Sharp Code:**

```
using System;
using System.Linq;
namespace exercises
{
class Program
{
static void Main(string[] args)
{
int n = 1;
Console.WriteLine("\nOriginal Number:" + n);
Console.WriteLine("Tetrahedral number:" + test(n));
n = 2;
Console.WriteLine("\nOriginal Number:" + n);
Console.WriteLine("Tetrahedral number:" + test(n));
n = 6;
Console.WriteLine("\nOriginal Number:" + n);
Console.WriteLine("Tetrahedral number:" + test(n));
}
public static int test(int n)
{
return n * (n + 1) * (n + 2) / 6;
}
}
}
```

Sample Output:

Original Number:1 Tetrahedral number:1 Original Number:2 Tetrahedral number:4 Original Number:6 Tetrahedral number:56

**Flowchart:**

**C# Sharp Code Editor:**

**Improve this sample solution and post your code through Disqus**

**Previous:** Write a C# Sharp program to get the Least Common Multiple (LCM) of more than two numbers. Take the numbers from a given array of positive integers.

**Next:** Write a C# Sharp program to sort a given positive number in descending/ascending order.

**What is the difficulty level of this exercise?**

Test your Programming skills with w3resource's quiz.

**Weekly Trends and Language Statistics**- Weekly Trends and Language Statistics