Is window in forecasting correct?

[gedeck]

The window has length 13, should it be length 12?

# code for forecasting one month ahead with sliding window 
forecast.ts <- c()
window <- norm_train.ts[(nTrain-12):nTrain]
for (i in 1:36) {
  x <- array(data=window, dim=c(1, ninput, 1)) 
  pred <- predict(lstm_model, x, batch_size=1) 
  window <-  c(window[2:length(window)], pred[1]) 
  forecast.ts <- c(forecast.ts, pred[1])
}