A model with one AR term, a first difference, and one MA term would have order (1,1,1). For the last model, ARIMA (1,1,1) , a model with one AR term and one MA term is being applied to the variableZt=Xt−Xt−1. A first difference might be used to account for a linear...
You could also check if x13results.stdout shows any information about the correct interpretation of the data. Author as4456 commented Mar 10, 2017 freq=12 gives the same results (It should anyways be provided if there is no date index). results.stdout does not provide any relevant informati...