During a conversation about programming, I meant to say:
I've seen a lot of programmers using that pattern.
I accidentally omitted the object and wrote:
I've seen a lot using that pattern.
For some reason that doesn't sound wrong to me. From context it is clear that I'm talking about software engineers without explicitly mention them, thus I don't need it for understanding. Quite the contrary, it would even be fine without repetition.
However, is that sentence OK without the object or should I use one of the following sentences?
I've seen a lot of them using that pattern.
I've often seen the use of that pattern.