Quote:
Originally Posted by wblipp
Hint:
The union of {composites > 1} and {primes > 1} is {integers > 1}

Ah, completely forgot about this bit.
The answer is 12/PiĀ² or 1.2158542037080532573265535585...
Also, just noticed the typo in my previous post. It's not ...  Zeta(s) but ... / Zeta(s), of course!