Whenever I do a forecast I always let gretl to do it for me and don't worry about anything else, the problem is that I need to send a spreadsheet to a client, and he "NEEDS" the calculation to be in there (Don't ask me why, he thinks that models are to photos not to math), anyway, I don't seem to find any reference that tells me how to forecast in a spreadsheet, I have an ARMA(2,3) model but I don't know how to make the MA forecast in a spreadsheet, the AR part is simple but the MA part I can't get past it, if someone has already done something similar please advice, I don't want an add-in or add-on or macro, I need it to be in a simple formula no matter if I need set the recursive formula option on, thanks in advance.