A BTree has a $k$ value that determines that every node has $k$ to $2k$ children. When a node has $2k$ keys it needs to be split into two nodes.
Let's say I want to create a $k/(2k-x)$ tree. (like a 2-3 tree that follows the BTree rules, but isnt $k/2k$)
What is the possible range of $x$? The tree must follow the behavior of a BTree, meaning it needs to hold keys and split accordingly.