Python - 使用固定alpha生成随机颜色列表的最快方法

So I'm looking to generate a large list of approximately 332 million colours (tuples with 4 values - r,g,b,a) in Python, but with a fixed alpha value of 0.6. I also need to duplicate every colour in the row below it (i.e. I end up with 664 million rows - only 332 million distinct colours.So I'm looking to generate a large list of appr