Surely there's a formula to calculate the number of trailing zeroes for n! in arbitrary bases; I can already figure out what's probably right, though not checked and requiring confirmation for edge cases: t(n, b) would be equal to the minimum of that-expression-you-see-there with 5 replaced with each prime factor of b, where the terms are integer-divided by the multiplicity of the prime. Or something like that.
Perhaps such a formula should be added to the article? I can't be the first one to think this out, and it seems like a useful bit of knowledge (or, well, just as useful as the factorial formula in the first place). Hppavilion1 (talk) 01:31, 21 March 2017 (UTC)