I found the Euler problems to be illuminating in Erlang. Its been several years now, but I had a decent primes module (https://github.com/jamesaimonetti/Project

I found the Euler problems to be illuminating in Erlang. Its been several years now, but I had a decent primes module (https://github.com/jamesaimonetti/ProjectEuler/blob/master/primes.erl https://github.com/jamesaimonetti/ProjectEuler/blob/master/p...) going that seemed fairly performant at the time. Granted, I was still quite the n00b when attempting these problems, so most solutions are probably not optimal, idiomatic, or useful; they were, however, great playgrounds in which to learn about Erlang. I also can't think of any of the problems I have in my repo that ran over the 1-minute time limit. So, I'd say Erlang has plenty of number crunching power for the low hanging problems in Euler (and probably efficient enough for the some of the more advanced ones, though I can't say for sure because I haven't tried them).