from typing import List


def generate(numRows: int) -> List[List[int]]:
    i = 1
    res = []

    while i <= numRows:
        if i == 1:
            res.append([1])
            i += 1

        elif i == 2:
            res.append([1, 1])
            i += 1

        elif i > 2:
            a = -1
            res.append([1, i + a, 1])
            a = i + a
            i += 1

    return res

print(generate(4))