def tribonacci(signature, n):
  """
  signature: list of 3 integers forming the basis of the tribonacci sequence
  n: numbers to return from the tribonacci sequence
  return: n numbers from the tribonacci sequence beginning with signature numbers
  """
  tribonacci_list = []
  for i in range(len(signature)):
    if i < n:
      tribonacci_list.append(signature[i])
  for j in range(2, n-1):
    tribonacci_list.append(tribonacci_list[-3]+tribonacci_list[-2]+tribonacci_list[-1])
  return tribonacci_list