Sequência de Tribonacci em JavaScript

function tribonacci(signature,n){  
  for (var i = 0; i < n-3; i++) { // iterate n times
    signature.push(signature[i] + signature[i+1] + signature[i+2]); // add last 3 array items and push to trib
  }
  return signature.slice(0, n); //return trib - length of n
}
Charming Crane