Find prime n such that reversed n is also prime

Find prime n such that reversed n 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 primen for that reversed n is also prime

Ring

<lang ring> load "stdlib.ring"

see "working..." + nl

row = 0 num = 0 limit = 500

for n = 1 to limit

   strm = ""
   strn = string(n)
   for m = len(strn) to 1 step -1
       strm = strm + strn[m]
   next
   strnum = number(strm)
   if isprime(n) and isprime(strnum)
      num = num + 1
      row = row + 1
      see "" + n + " "
      if row%10 = 0
         see nl
      ok
    ok       

next

see nl + "found " + num + " primes" + nl see "done..." + nl </lang>

Output:

working...
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 
found 34 primes
done...