(This video is no longer available for streaming.) Prime numbers—those that can only be divided by themselves and one—bear a mystery. Why do primes tend to pair up? Five and seven, for example, are prime, as are 41 and 43, and 101 and 103. For millennia, mathematicians have wondered: Does this continue no matter how high one counts? As this video and its original song reveal, a mathematician has just given us an answer to this age-old enigma.