Suppose, a prime $\ p\ $ is given.
How can I check efficiently whether the distance to the nearest prime is $\ d\ $ or more , if $\ d\ $ is given ?
My approach is to start with $\ c=2\ $ and as long as $\ p-c\ $ and $\ p+c\ $ are both not prime increasing $\ c\ $ , the distance of the nearest prime is then $\ c\ $
Can I , apart from some trial divisions , accelerate the procedure somehow ?