# Number of triplets of collinear points in a standard setting

This might be a stupd inquiry, but I was working on something and stumbled upon this question: if say we are given $n$ points in plane that determine $k$ distinct lines, what is the number of triplets of collinear points?

Any help would be really appreciated

Sorry if it turns out to be too trivial or too hard to find some bounds. (I'm just tired of thinking about it without luck)

Thanks!

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