> You could argue that mathematics are "art" but then you would need a really wide and probably useless definition of "art" as almost everything would be art.
I don't think that everyone (maybe not even every mathematician) would call math an art, but I think that it can be done without doing undue violence to the term. For me, what makes mathematics an art is its capability for creating and exploring unusual, surprising, sometimes delightful patterns, in visual and other senses of the term. I'm not sure I'd call that a definition of 'art', but I think that it's not so broad as to be meaningless.
(A quick Google for "math is art" turns up many other (probably better) arguments along the same theme. Here's one: https://hackernoon.com/mathematics-is-art-all-the-mathematic... .)