Determining Values

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I have tried a couple of ways to get started / finish this problem but I cant seem to figure out how to fully explain and determine the value of $x_n$. I have posted my question below with figures to help explain.

I know that recurrence-relation must be used to determine the values but if its possible if you can provide sample examples that relate this question. That would be great

If I let $n \geq 1$ be an integer and use a $2 \times n$ board $D_n$
containing $2n$ cells, each side has a length of 1. T

The brick can be vetical or horizontal containg $2$ cells(explained in the bottom part of the above picture).

The tiling of board ($D_n$) is placed with bricks so that :

1.item the bricks exactly cover $D_n$ and

2.item no two bricks overlap.

So for $n \geq 1$, we let $x_n$ become number of different tilings of the board $D_n$. And I have to Determine the value of $x_n$ but I cant seem to figure it out any help or guideance would be greatly appericated.

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Hint: You're probably best off looking at a recurrence relation.

Note that there are only two ways to cover the left-most two squares: either a single vertical brick, or two horizontal bricks. What does this tell you about how you can write $x_n$ in terms of $x_{n-1}$ and $x_{n-2}$?

Note that if you cover those two left ones with a single vertical brick, what's left is to choose any covering of the other $n-1$ columns... and the way to do this is precisely $x_{n-1}$. So, there are $x_{n-1}$ arrangements in which you cover the left two by a vertical brick.

What if you use two horizontal bricks? Then you've knocked out two columns, and need to pick a covering of the remaining $n-2$ columns...

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Hint: Try to get a reccurence relation for $D_n$. What is $D_n$ in relation to $D_{n-2}$?