P Value from Pearson r

I am not sure if this is the correct place to ask this question, but forgive me for having a try if wrong.

If have a fairly extensive spreadsheet from which I calculate Correlation/Pearson data, giving me an "r" number.

There are tables on the internet for "P" numbers for comparison. I cannot find anywhere either the formula/equation for these tables, or anything like it within Excel 2007.

I will attach below a table from the internet. My aim is to have a formula/equation that I can put in a cell to give me the table answers. In other words if by example a formula for if N=5 and CI = .05 then 0.80 etc.

I hope I have explained myself.

Many Thanks