I'm trying to find a way to estimate the number of weights in a neural network. Let's look a simple example.

nnetar(1:10) (from the forecast package) gives me a 1-1-1 Network with 4 weights.

That makes total sense to me, since we see four arrows in the illustration.

However, nnetar(1:10, xreg=data.frame(10:1,3:12)) gives me a 3-2-1 Network with 11 weights

I don't understand, why the output says that there are 11 weights involved, since I count 12!? Any suggestions?