with cte_r as(
    select 2 as n 
    union all 
    select n+1 from cte_r where n < 1000  
),

check_prime as(
    select a.n 
    from cte_r a 
    left join cte_r b 
    on b.n >= 2 
        and b.n <= sqrt(a.n) 
        and a.n % b.n = 0
    where b.n is null
)
SELECT STRING_AGG(n, '&') 
       WITHIN GROUP (ORDER BY n)
FROM check_prime
OPTION (MAXRECURSION 1000);