Definitions
In mathematics, additive primes are prime numbers for which the sum of their decimal digits are also primes.



Task
Write a program to determine (and show here) all additive primes less than 500.

Optionally, show the number of additive primes.



Also see

   the OEIS entry:   A046704 additive primes.
   the prime-numbers entry:   additive primes.
   the geeks for geeks entry: additive prime number.
   the prime-numbers fandom: additive primes.


function sumdigits(n)
  local sum = 0
  while n > 0 do
    sum = sum + n % 10
    n = math.floor(n/10)
  end
  return sum
end
 
primegen:generate(nil, 500)
aprimes = primegen:filter(function(n) return primegen.tbd(sumdigits(n)) end)
print(table.concat(aprimes, " "))
print("Count:", #aprimes)