primes

This question already has an answer here: Which is the fastest algorithm to find prime numbers? 14 answers First of all - I checked a lot in this forum and I haven't found something fast enough . I try to make a function that returns me the prime numbers in a specified range. For example I did this function (in C#) using the sieve of Eratosthenes. I tried also Atkin's sieve but the Eratosthenes one runs faster (in my implementation): public static void SetPrimesSieve(int Range) { Primes = new List<uint>(); Primes.Add(2); int Half = (Range - 1) >> 1; BitArray Nums = new BitArray(Half, false);

How can I generate a large random prime using openssl, I found out how to generate a random number and check if it is prime but I have not been able to automate the process of checking the primality, here is the command that i am using: openssl rand -hex 256 | xargs openssl prime -hex Should I use a while loop to repeatedly check if the result is prime? How can I automate the process of checking if the result does not contain the keyword "not", This is all the further i got on writing the while loop: while [{openssl rand -hex 256 | xargs openssl prime -hex} = *"$not"*] OpenSSL version 1.0.0

This code was taken from the book "Haskell Road to Logic, Math and Programming". It implements sieve of eratosthenes algorithm and solves Project Euler Problem 10. sieve :: [Integer] -> [Integer] sieve (0 : xs) = sieve xs sieve (n : xs) = n : sieve (mark xs 1 n) where mark :: [Integer] -> Integer -> Integer -> [Integer] mark (y:ys) k m | k == m = 0 : (mark ys 1 m) | otherwise = y : (mark ys (k+1) m) primes :: [Integer] primes = sieve [2..] -- Project Euler #10 main = print $ sum $ takeWhile (< 2000000) primes Actually it runs even slower then the naive prime test. Can someone explain this

I am working on a prime factorization program implemented in Java. The goal is to find the largest prime factor of 600851475143 ( Project Euler problem 3 ). I think I have most of it done, but I am getting a few errors. Also my logic seems to be off, in particular the method that I have set up for checking to see if a number is prime. public class PrimeFactor { public static void main(String[] args) { int count = 0; for (int i = 0; i < Math.sqrt(600851475143L); i++) { if (Prime(i) && i % Math.sqrt(600851475143L) == 0) { count = i; System.out.println(count); } } } public static boolean Prime

There is the problem of trying to see if two unique strings are anagrams of each other. The first solution that I had considered would be to sort both strings and see if they were equal to each other. I have been considering another solution and I would like to discuss if the same would be feasible. The idea would be to assign a numerical value to each character and sum it up such that a unique set of characters would produce a unique value. As we are testing for anagrams, we do not mind if the checksum of "asdf" and "adsf" are the same -- in fact, we require it to be that way. However the