Increase numbers cell value daily

I'm trying to figure out how to set a cell value to increase daily. For example, using calendar year 2020, I would like to set the value to 28 for 1 Jan, then have it automatically increase by 28 each day for the remainder of the year. So if I open the document on 10 Jan, the cell value would auto update to 280 (28 x 10 days).