[dbaupp]

Seriously? The discussion is about language features, not optimal algorithms.

One could imagine the question was actually "sum BusyBeaver(n) for n divisible by 3 and 5 between 1 and 100", i.e. no closed form. In Python:

  sum(BusyBeaver(x) for x in xrange(1,101) if x % 3 == 0 and x % 5 == 0)

(And yes, if one was being really pedantic, one could replace the condition with x % 15 == 0.)

[darkestkhan]

The thing is that people start using those libraries w/o thinking before - and theirs' solutions end up doing much more work than is needed

[delinka]

This could be said of most anything high level.