Uhhh. Look. Just because you're using this narrow definition of "purpose" doesn't mean that everybody is. Nor, that because science hasn't posited a value for your n term, it says we have no purpose.
It has nothing to say about the purpose of humanity or the universe. It has no evidence about the purpose of either. All the anthropomorphic "Science" has to say about the purpose of the universe and humanity is: "Oooo, this (humanity, the Universe, Marshmallow Fluff) is kinda neat, why don't we try to understand the mechanisms that underpin it?" Science looks at things. It describes and predicts the behaviours of things. It does NOT answer the question "why" in any meaningful way, beyond "to be understood."