def triangle(n):
    return_triangle = []
    if n == 0:
        return return_triangle
    if n == 1:
        return return_triangle.append([1])
    recurse_triangle = triangle(n-1)
    prev_row = recurse_triangle[-1]
    curr_row = [1]
    for i in range(len(prev_row)-1):
        current_row.append(prev_row[i] + prev_row[i+1])
    curr_row.append(1)
    return_triangle.append(curr_row)
    return