Different ways to put n distinguishable balls in k distinguishable boxes, when every box has to have an even amount of balls?

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I've been learning about combinatorics, and up until now I have an okay understanding of generating functions and some basic situations like putting (in)distinguishable balls into (in)distinguishable boxes. The following problem stumps me, however: If we are given $n$ distinguishable balls and $k$ distinguishable boxes, in how many ways can we put the balls into the boxes, given that we are only allowed to put an even amount of balls into any given box? I tried writing out a couple of small cases to see if I could find a pattern, but this didn't get me far: could I use (exponential) generating functions here?