Primes whose reversed number is also prime

Primes whose reversed number is also prime is a draft programming task. It is not yet considered ready to be promoted as a complete task, for reasons that should be found in its talk page.

Task

Find and show here in base ten primes whose reversed number is also prime and not equals, where n < 1,000

Ring

<lang ring> load "stdlib.ring" see "working..." + nl see "Primes whose reversed number is also prime:" + nl row = 0

for n = 1 to 1000

   strn = string(n)
   strn = rever(strn)
   strn = number(strn)
   if isprime(n) and isprime(strn) and n != strn
      see "(" + n + "," + strn + ")" + " "
      row++
      if row%5 = 0
         see nl
      ok
   ok    

next

see nl + "Found " + row + " prime numbers" + nl see "done..." + nl

func rever(str)

    strb = ""
    for n = len(str) to 1 step -1
        strb += str[n]
    next
    return strb

</lang>

Output:

working...
Primes whose reversed number is also prime:
(13,31) (17,71) (31,13) (37,73) (71,17) 
(73,37) (79,97) (97,79) (107,701) (113,311) 
(149,941) (157,751) (167,761) (179,971) (199,991) 
(311,113) (337,733) (347,743) (359,953) (389,983) 
(701,107) (709,907) (733,337) (739,937) (743,347) 
(751,157) (761,167) (769,967) (907,709) (937,739) 
(941,149) (953,359) (967,769) (971,179) (983,389) 
(991,199) 
Found 36 prime numbers
done...