# Kata – Tribonacci Sequence I did a codewars Kata tonight and it went quickly for once! It was called the Tribonacci sequence and it is creating a fibinacci sequence that sums three numbers instead of two. Conceptually it is pretty understandable, and my resulting code was relatively slim.

``````function tribonacci(signature,n){
if (n===0) return []; //short circuit on 0
let outArray = [...signature]; //start the sequence
for (let i=3; i<n; i++){
outArray.push(outArray[i-3]+outArray[i-2]+outArray[i-1])
}
if (n<=3){ //return the right # if it is below 4
return outArray.slice(0,n);
}
return outArray //otherwise smooth sailing
}

tribonacci([1,2,3],20);``````

This time I expected all sorts of weird edge cases, but I passed the test on the first shot! I actually liked the simplifications that the top rated answer had, so I’ll refactor a few into the result below

``````function tribonacci(signature,n){
for (let i=3; i<n; i++){
signature.push(signature[i-3]+signature[i-2]+signature[i-1])
}
return signature.slice(0,n); //this line alone will return empty
} // on n=0 and correct when n<=3``````

I think this is most likely one of the easier katas I have run into, but it’s still nice to get a quick win in every once in a while. I thought it was interesting to see how they used the signature variable as opposed to holding it in a new one. That saved a line right there.

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