I’ve not personally verified the correct implementation  but there was a parallel Pytorch and Keras impl at:

  
      

      GitHub
  

  
    

GitHub - philipperemy/n-beats: Keras/Pytorch implementation of N-BEATS:... 1

  Keras/Pytorch implementation of N-BEATS: Neural basis expansion analysis for interpretable time series forecasting. - GitHub - philipperemy/n-beats: Keras/Pytorch implementation of N-BEATS: Neural ...