WITH RECURSIVE numbers(n) AS (
    SELECT 2
    UNION ALL
    SELECT n + 1 FROM numbers WHERE n < 1000
),
divisors(d) AS (
    SELECT 2
    UNION ALL
    SELECT d + 1 FROM divisors WHERE d < 1000
)
SELECT GROUP_CONCAT(n SEPARATOR '&')
FROM numbers
WHERE NOT EXISTS (
    SELECT 1 FROM divisors
    WHERE divisors.d < numbers.n AND numbers.n % divisors.d = 0
);