News for hackers. Stuff that matters.

A comment on Why do prime numbers make these spirals?. Parent comment

Re:Why do prime numbers make these spirals? by leoff on Wednesday April 26, 2023 @06:26AM (#35711586)
>all primes greater than 3 are of the form 6k+1 or 6k-1

what's the value in using this "formula"? We could also keep extending this rule, and say that all primes greater than 5 are of the form 30k±1, 30k±7, 30k±11, or 30k±13. Or go further by multiplying coefficient of X with the next primes

[ Parent | on HN ]
Re:Why do prime numbers make these spirals? by Vvector on Wednesday April 26, 2023 @10:05AM (#35713831)
30k±1 = 6x±1 where x = 5k and so on. Why use four formulas when one will suffice?
[ Parent | on HN ]
Re:Why do prime numbers make these spirals? by zamadatix on Wednesday April 26, 2023 @07:09PM (#35721194)
For the same reason you'd use 6x±1 instead of 1+2n or, more basically, n - higher check hit rate at the cost of more complex checking rules.
[ Parent | on HN ]