And is an infinite enumerable still enumerable?
Enumerable, in this sense, is based off the second definition of enumerate:
to specify one after another
It is not referring to the (more common outside of computing) definition whereby it effectively means "able to be counted."
In this sense, an infinite series can definitely be listed one item after another, and qualifies as an enumerable.
That being said, I don't see the purpose behind your code in this example. Infinite enumerables are typically representing something like a stream of data without an end, or other sources where there is no "end", but the potential to continually pull information.