Hehe - we're just doing primes up until 1001 I think now eddygp - it's all a bit too easy to get to any 3 figure number so as long as we can make all the primes we'll assume the rest are pretty simple.
For those who have been asking about the meanings of different symbols and functions, I've just been backwards and forwards through wikipedia's maths section and found every function that I think could be useful. I'll hide them in a spoiler in case people don't want to see them, but this isn't a template to just read off the answers, just a description of how all the different functions work. I've left out a few that aren't really useful.
We've used most of them, but there's a few here we haven't touched yet that may come in handy as we get higher targets.
I'm fine with more functions. The main reason why I dislike the ceiling/floor functions is that you can abuse them to essentially get any number you want out of a single 5 by just using repeated square rooting and random other functions.
Also, I can't figure out 373 without using the ceiling/floor functions.
I think we've always been able to use any function, just now I've made a list of them that's as complete as I can find infor for - we still can use floor/ceiling but maasman and I are avoiding them if possible.