SARIMA Equation

#1
Hello everyone,
I am currently using ARIMA and SARIMA models to forecast a company´s sales. I get the general idea of the models, but i cannot seem to understand the exact equation stata uses to predict the model´s output.
My dataset is comprised of 120 monthly observations of sales "altom" and the command i use to model the sales is the following:

arima d.altom, noconstant ar(1) ma(1) mar(1, 12) mma(1, 12)
predict model

What i want stata to tell me is the equation it uses with the command "predict" after running the model.
I looked at the stata manual but all the examples there aim to model the difference of the seasonality, as if the command was:
arima ds12.altom, noconstant ar(1) ma(1) mar(1, 12) mma(1, 12)

Thanks everyone in advance!