I like your naming scheem

Yeah, but that's what "return a == (int)a ? (long)a : -1;" does. If it has decimals it will return -1, else it will return a;
I figured since it passed all the other tests that there was something this formula didn't account for. Something I could fix :P
Anyways, thanks for the kata :D

Not applicable in some languages.

There are only integers so you should not use floats.

I tried avoiding reccurcivity and therefore solving for n, but a lot of the solutions ar just force-bruting it like trying until it maches or excedes...

I would've added a test with a n an order of magnitude greater, like m = 2↑↑10 (n = 2.5*10^45) or smthg, exciding the 12'000ms timer for reccurcive methodes

Nonetheless, it was a great kata, fun to solve