I knew you would come up with a cleverer solution
And indeed, series could have not an index of 1. My improvement would be (I like to keep code small):
Code:
series:true and series_index:"<=1"
This will find 0, 0.n and 1.
I have the impression
Code:
template:"""{series_index}#@#:n:<=1"""
is quicker, though (1 comparison less)