# Prime Numbers

I know there are few that appreciate numbers as much as me. If you’re not one of them, stop reading now.

Wikipedia is loaded with information on numbers. I have been focusing lately on prime numbers. Wikipedia lists 59 different “kinds” of prime numbers. A prime fits into a specific category if it is prime and has some other special characteristic.

For example, a prime (i) is a twin prime if (i-2) *or* (i+2) is also prime. That is, 5 and 7 are twin primes, but 13 and 17 are not.

Another interesting class of primes is “Illegal Primes”. Illegal primes are numbers that are prime and also *illegal*. The web quotes only two numbers to be potentially illegal primes. The numbers could be considered illegal because their *binary representation* could be deemed illegal.

The example of this is the DVD decrypting program DeCSS. That is, the DeCSS application could be archived (merely to allow for padding, I guess). It’s binary code could then be converted to the decimal equivalent of a prime number, thus making the decimal number illegal. (by *decimal* I mean base-10, not a number with a decimal point.)