алгоритм "Решето Эратосфена" используется для поиска простых чисел Смотри также: prime number
математика решето Эратосфена
a procedure for finding prime numbers that involves writing down the odd numbers from 2 up in succession and crossing out every third number after 3, every fifth after 5 including those already crossed out, every seventh after 7, and so on with the numbers that are never crossed out being prime