In this MO question, user Martin Brandenburg asks about God's number for $n \times n \times n$-cubes for $n>3$. Here, God's number $g(n)$ was defined as the smallest number $m$ such that every realizable arrangement of the $n \times n \times n$-cube can be solved within $m$ moves.
We could generalize the notion of God's number to $n^{k}$-cubes, where $k >3$ is the number of dimensions. Define $g_{k}(n)$ as the smallest number $l$ such that every realizable arrangement of the $n^{k}$-cube can be solved within $l$ moves.
Whereas Mr. Brandenburg's question pertains to three dimensional Rubik's cubes ($k=3$), I wonder what is known about higher God's number for higher dimensional sequential move puzzles.
Questions:
- Is $g_{4}(2)$ known? And what about $g_{4}(3)$?
- What is known about the asymptotic value of $g_{k}(n)$?