Calculate the growth multiplier constant for a given server and threads.
The actual amount of money grown depends both linearly \*and\* exponentially on threads; this is only giving the exponential part that is used for the multiplier. See [grow](./bitburner.ns.grow.md) for more details.
As a result of the above, this multiplier does \*not\* depend on the amount of money on the server. Changing server.moneyAvailable and server.moneyMax will have no effect.
For the most common use-cases, you probably want either [formulas.hacking.growThreads](./bitburner.hackingformulas.growthreads.md) or [formulas.hacking.growAmount](./bitburner.hackingformulas.growamount.md) instead.