Python function to generate n rows of a Tribonacci Triangle.

tribonacci_triangle.py

def tribonacci_triangle(n):
  # n <-  number of rows to generate
  # a <- tribonacci triangle 
  a = [[1], [1, 1]]
  if n == 1:
    return [[1]]
  elif n == 2:
    return a
  else:
    # generate rows 3 to n
    for i in range(3, n + 1):
      # generate row n elements
      # b <- row n
      b = [1]
      for j in range(1, i - 1):
        b.append(a[i - 3][j - 1] + a[i - 2][j - 1] + a[i - 2][j])
      b.append(1)
      a.append(b)
      b = [1]
    return a

print(tribonacci_triangle(7))