A=2x3x5x7x11x13x17........ up to
A-pm= A number factorable by a factor of pif p has one.
To get A-pm, go through the primes, subtracting p as many times as you like.
In this way we can find out if p is composite without ever having to use a number. Might be useful for computers.
"Time not important. Only life important." - The Fifth Element 1997