NAME
     factor - discover prime factors of a number

SYNOPSIS
     factor

DESCRIPTION
     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 256 (about 7.2e16) it will factor the number and
     print its prime factors; each one is printed the proper num-
     ber 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 sqrt(n) and occurs
     when n is prime or the square of a prime.  It takes 1 minute
     to factor a prime near 1013.

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

BUGS

 1