Java Program for Triangular Matchstick Number

Given a number X which represents the floor of a matchstick pyramid, write a program to print the total number of matchstick required to form a pyramid of matchsticks of x floors.

Examples:

Input : X = 1 Output : 3 Input : X = 2 Output : 9

This is mainly an extension of triangular numbers. For a number X, the matchstick required will be three times of X-th triangular numbers, i.e., (3*X*(X+1))/2

`// Java program to find X-th triangular ` `// matchstick number ` `public` `class` `TriangularPyramidNumber { ` ` ` `public` `static` `int` `numberOfSticks(` `int` `x) ` ` ` `{ ` ` ` `return` `(` `3` `* x * (x + ` `1` `)) / ` `2` `; ` ` ` `} ` ` ` `public` `static` `void` `main(String[] args) ` ` ` `{ ` ` ` `System.out.println(numberOfSticks(` `7` `)); ` ` ` `} ` `} ` |

**Output:**

84

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