Rebol3 Code Examplex

Find prime n such that reversed n is also prime

Search for primes whose digit reversal is also prime.

Rebol [
    title: "Rosetta code: Find prime n such that reversed n is also prime"
    file:  %Find_prime_n_such_that_reversed_n_is_also_prime.r3
    url:   https://rosettacode.org/wiki/Find_prime_n_such_that_reversed_n_is_also_prime
]

print collect [
    repeat n 499 [
        if all [
            prime? n
            prime? to integer! reverse form n
        ][  keep n ]
    ]
]

Output:

2 3 5 7 11 13 17 31 37 71 73 79 97 101 107 113 131 149 151 157 167 179 181 191 199 311 313 337 347 353 359 373 383 389