|Thanks to both Humar and DerbyDad both your suggestions worked. And derbyDad's second formula is especially helpful since I also want to vary the value of n to be various prime numbers to go up the integers in steps of 47 for instance. |
The series of numbers derived from 6n+or-1 where n = the series 1,2,3,4....n contains mixed in it all primes over 3. once we have the first few primes we can I take any prime such as 47 then square it = 2209.
the 6n+or-1 numbers between 47 & 2209 but not equal to 2209 will only need to be checked for primality by dividing them only by the primes below 47. this will give all the primes in the range we have defined above 47.
I don't imagine there is a formula for that little lot! but that is why I needed to create the series that you helped me with.
I cobbled together the following to check the 47 series:
if either of you feel strong enough to improve on that mouthful I would be grateful since the next series goes up to over 4 million and I don't think this way of filtering the results will be very effective!
edited by moderator: Formula Split Into Multiple Lines