(49g 50g) Number of Trailing Zeros in N!

[John Keith]

Thanks for posting this, Thomas. Your program is certainly simpler, although it is limited to numbers < 10^12.

The reason for my rather brute-force approach is to allow number sizes limited only by the calculator's memory while avoiding the slowness of the HP50 IQUOT function. I am working on a revised version that should allow numbers with several thousand digits (that is the number n itself, not n!).

As shown in this paper from the OEIS link above, this method can be extended to numbers with arbitrary base. Doing so is not entirely straightforward because the details seem to depend on whether the base b is a prime, semiprime, prime power, etc. As they say, further research is needed.