factor, primes - factor a number, generate large primes factor [ number ]

primes

When factor is invoked without an argument, it waits for a number to be typed in. If you type in a positive number less than 2\u\s756\s0\d (about it will factor the number and print its prime factors; each one is printed the proper number of times. Then it waits for another number. It exits if it encounters a zero or any non-numeric character.

If factor is invoked with an argument, it factors the number as above and then exits.

Maximum time to factor is proportional to and occurs when n is prime or the square of a prime. It takes 1 minute to factor a prime near 10\u\s714\s0\d on a PDP11.

When primes is invoked, it waits for a number to be typed in. If you type in a positive number less than 2\u\s756\s0\d it will print all primes greater than or equal to this number.

`Ouch.' for input out of range or for garbage input.