How to write a time series model

[NemanjaV]

Hi guys!
I have estimated c ar(1) ar(12) model, because there was certain autocorrelation on k=12. Its monthly data, series has one unit root.
How to write this model?
reduced ARIMA(12,1,0) or
ARIMA(1,1,0)x(1,0,0)?

I must say sar(12) is not significant. 

[Ksharp]

Are you trying to fit a Time Series Mode ?  Plz post it at 

SAS Forecasting and Econometrics

Or are you trying to simulate Time Serise Data ? Plz post it at 

SAS/IML Software and Matrix Computations