Quote:
Originally Posted by science_man_88
this what you want ?

No, I think not!
Those small twins are all known (see list at download or the summarypages).
He was asking of higher nlevels say n~500000 for any prime of the form k*2^n1.
Test those k/npairs if the number k*2^n+1 is prime, too! The Rieselside (1) is known to be prime for many values here but none has ever tested the '+1'side!
OTOH the chance for finding a new twin by testing only these primes is very low.