<h2 id="heading-url">URL</h2>
<p><a target="_blank" href="https://leetcode.com/problems/n-th-tribonacci-number/description/">N-th Tribonacci Number - LeetCode</a></p>
<h2 id="heading-code">Code</h2>
<p><a target="_blank" href="https://github.com/syohex/dotnet-study/tree/master/fsharp/leetcode/problems/1137/main.fsx">https://github.com/syohex/dotnet-study/tree/master/fsharp/leetcode/problems/1137/main.fsx</a></p>
<pre><code class="lang-plaintext">let tribonacci (n: int) : int =
    let rec tribonacci' i n prev3 prev2 prev1 =
        if i &gt; n then
            prev1
        else
            tribonacci' (i + 1) n prev2 prev1 (prev3 + prev2 + prev1)

    match n with
    | 0 -&gt; 0
    | 1
    | 2 -&gt; 1
    | _ -&gt; tribonacci' 3 n 0 1 1
</code></pre>


## URL

[N-th Tribonacci Number - LeetCode](https://leetcode.com/problems/n-th-tribonacci-number/description/)

## Code

[https://github.com/syohex/dotnet-study/tree/master/fsharp/leetcode/problems/1137/main.fsx](https://github.com/syohex/dotnet-study/tree/master/fsharp/leetcode/problems/1137/main.fsx)

```plaintext
let tribonacci (n: int) : int =
    let rec tribonacci' i n prev3 prev2 prev1 =
        if i > n then
            prev1
        else
            tribonacci' (i + 1) n prev2 prev1 (prev3 + prev2 + prev1)

    match n with
    | 0 -> 0
    | 1
    | 2 -> 1
    | _ -> tribonacci' 3 n 0 1 1
```

1137. N-th Tribonacci Number in F#

URL

Code